For the most part, you may only make changes to your Medicare coverage during the Annual Enrollment Period (AEP) and Medicare Advantage Open Enrollment. However, Medicare understands that not all of life's changes happen during those periods. That's why the program includes Special Enrollment Periods (SEPs).

This post explains when you can make changes to your Medicare Advantage, Medigap, or Part D plan. But first, you need to understand Medicare's different enrollment periods.

When Is the Initial Enrollment Period?

Your Initial Enrollment Period (IEP) occurs during the seven months surrounding your 65th birthday. This includes the three months before your birthday, the month of your birthday, and the three months following your birthday. So, if your birthday is June 15, your IEP begins on March 1 and ends on September 30.

What Is the Annual Enrollment Period?

The Annual Enrollment Period (AEP) is your yearly opportunity to make changes to your Medicare coverage. If you are currently enrolled in Medicare, you may take advantage of AEP to do any of the following:

• Leave Original Medicare for a Medicare Advantage (MA) plan
• Switch back to Original Medicare
• Change from one MA plan to another
• Sign up for a new Medicare Part D prescription drug plan

AEP begins October 15 and ends December 7. Coverage begins January 1 of the following year.

What Is Medicare Advantage Open Enrollment?

Medicare Advantage Open Enrollment is available to all beneficiaries currently enrolled in an MA plan. It starts on January 1 and continues through March 31. During this time, you may switch to a new Medicare Advantage plan or return to Original Medicare. If you're returning to Original Medicare, you may also join a new Part D plan. However, you may not use this period to leave Original Medicare to join an MA plan.

What Is the General Enrollment Period?

Medicare offers the General Enrollment Period (GEP) for those who did not sign up for Medicare when they first became eligible AND are not eligible for an SEP.

GEP runs from January 1 to March 31 and allows you to sign up for Medicare Parts A and B. Coverage begins July 1 and requires paying premiums for Part A and/or Part B. Please note that you may face higher premiums due to enrolling late.

What Are Special Enrollment Periods?

Special Enrollment Periods are similar to the change of life exceptions offered by many employer-sponsored group insurance plans. If you experience what Medicare calls special circumstances, you may be able to make changes to your Medicare plans outside of the enrollment periods covered above.

There are literally dozens of special circumstances that qualify you for an SEP. We cover them in detail at the end of this article.

When Can I Change My Medicare Advantage Plan?

These are the most frequently asked questions we see regarding when you can change your MA plan.

Can I change my Medicare Advantage Plan during the Initial Enrollment Period?

Yes, you may change your Medicare Advantage plan during your Initial Enrollment Period. You may wish to make a change if you fail to notice that your doctor is not included in the plan's network. Another common reason is that the drug formulary does not cover one or more of your prescriptions. This is why comparing your Medicare Advantage plan options is so important.

Can I Change My Medicare Advantage Plan During Annual Enrollment?

Yes, you may make a variety of changes to your Medicare coverage during AEP. This includes leaving Original Medicare for an MA plan, leaving an MA plan for Original Medicare, switching from one MA plan to another, and enrolling in a new Part D plan.

Can I change my Medicare Advantage Plan during Medicare Open Enrollment?

Yes, this is literally what the Open Enrollment Period is for – it allows people currently enrolled in a Medicare Advantage plan to switch to a new plan. You may also choose to leave your MA plan to return to Original Medicare.

Can I change Medicare Advantage plans during a Special Enrollment Period?

If you qualify for a Special Enrollment Period then yes, you may change to a new MA plan. The most common reasons people use an SEP to find a new Advantage plan are:

• Moving outside your current plan's service area
• Moving to an area that offers more plan options
• Medicare terminating your plan
• Moving into a long-term care or skilled nursing facility

Common Reasons to Change Medicare Advantage Plans

There are a number of reasons people decide they want a new Medicare Advantage plan. Common examples include:

• You face rising out-of-pocket costs and want to find a plan with a lower out-of-pocket maximum
• You want an MA plan with more comprehensive coverage, such as prescription drugs or routine dental care
• Your medical needs are relatively low so you want a more basic plan with fewer bells and whistles
• Your prescriptions cost too much under your current plan
• You want to switch plan types, such as leaving an HMO (health maintenance organization) for a PPO (preferred provider organization)

If you're ready to compare your Medicare plan options, our Find a Plan tool makes it easy. Just enter your location and start date to see which plans are available in your area.

When Can I Enroll in a Medicare Supplement Insurance Plan?

Commonly known as Medigap, Medicare Supplement Insurance policies help you pay some of the costs not covered by Original Medicare. Private insurers underwrite these policies. This means that you can be denied a Medigap policy if you do not meet the underwriting requirements. However, if you buy a policy during your Medigap Open Enrollment Period, you cannot be denied a policy or charged a higher premium.

Medigap Open Enrollment begins the month you are both 65 or older and enrolled in Medicare Part B. It lasts for six months.

When Can I Switch from Medicare Advantage to Medigap?

You may only enroll in a Medicare Supplement Insurance plan if you have Original Medicare. Technically, you may apply for a Medigap policy at any time. However, unless you sign up during your Medigap IEP, you face medical underwriting unless you meet one of these special circumstances:

• If you leave your first Medicare Advantage plan within 12 months, you qualify for what's known as "trial rights"
• Moving outside of your MA plan's service area allows you to return to Original Medicare and buy a Medigap plan without undergoing medical underwriting

If neither of these circumstances apply, you may still be able to buy a Medigap plan. But, if you have any preexisting health conditions, you may be denied coverage or be charged higher premiums. That's why it's so important to buy a Medigap policy as soon as you are able.

Can I Suspend My Medigap Plan?

There are two scenarios in which you may suspend your Medigap coverage.

Putting Medigap on hold when you get other coverage

If you are under 65 and qualify for Medicare due to disability, you may suspend your Medigap coverage if you go back to work and your employer offers group health insurance. You may also put your policy on hold if you are the dependent of someone (such as a parent or spouse) whose job provides health insurance.

To suspend your Medigap plan, contact your provider. If you lose your group coverage, you have 90 days to reinstate your Medigap policy.

Putting Medigap on hold if you get Medicaid

If you qualify for Medicaid, you may put your Medigap policy on hold within 90 days of your Medicaid coverage beginning. Notification should be made in writing, but call your provider for details.

You may suspend your Medigap policy for up to two years.

Please note that, if you already have Medicaid when you become eligible for Medicare, it is illegal for anyone to sell you a Medigap policy unless Medicaid pays either your Medigap or Medicare Part B premium (in total or in part).

Can I Leave Medigap to Join a Medicare Advantage Plan?

When choosing to supplement your Original Medicare coverage, you must decide between Medigap and Medicare Advantage; you cannot have both. If you decide to join an MA plan, you must first cancel your Medigap policy. You may do this during any of the enrollment periods listed above or if you qualify for one of the Special Enrollment Periods.

If you decide to return to Original Medicare AND this is the first time you've had a Medicare Advantage plan, you qualify for "trial rights." This allows you to return to your original Medigap policy without undergoing medical underwriting. If you do not change back within the first 12 months or if this wasn't your first time enrolling in an MA plan, you may be denied Medigap coverage based on underwriting.

When Can I Change My Medicare Part D Plan?

All Medicare beneficiaries may choose a new Part D plan during Annual Enrollment. Additionally, you may enroll in a new Medicare Part D plan if you return to Original Medicare during the Medicare Advantage Open Enrollment Period.

Beneficiaries who qualify for Extra Help may change to a new Part D plan every quarter leading up to AEP:

• January – March
• April – June
• July – September

You may also change your Part D plan if you qualify for an SEP, such as moving away from your plan's service area.

Can I Change Part D Plans If the Drug Formulary Changes?

The drug formulary is the list of prescription drugs covered by your plan. Many Part D plans change their drug formulary throughout the year. When this happens, your plan must notify you 60 days before the change takes place.

Please note that, even if the formulary changes, your plan must continue covering your medication unless one of the following applies:

• There is a safety issue with your medication
• A generic version of your drug is available

One reason we advise Medicare beneficiaries to review their plans carefully during Annual Enrollment is that Part D formularies often change during the year. Even though your plan had to continue covering your medication, it won't have to next year. Always review a prescription drug plan's formulary carefully to ensure it covers your medications.

What Are Special Circumstances?

To qualify for one of Medicare's Special Enrollment Periods, you must meet one of the special circumstances listed below.

You have a permanent change of address

If you have a permanent change of address, you have up to 4 months to make changes to your Medicare Advantage or Part D plans. This includes:

• Moving to an address outside your plan’s service area
• Moving back to the United States after living abroad
• Moving into or out of an institution
• Being released from jail

If you notify your plan about your change of address before moving, you get 4 months to find a new plan. It starts the month before your move date and ends two full months after you move. Waiting until after you move gives you only 3 months: the month you move plus the two months after.

You lose your current coverage

In most circumstances, if you lose coverage, you have two months to join an MA or Part D plan, or to return to Original Medicare. This includes losing Medicaid eligibility, creditable drug coverage, and dropping PACE coverage. The one difference is if you lose coverage through your or your spouse’s employer, in which case you have eight months to make these changes.

If you discover that you will lose Medicaid eligibility next year, your change window runs from January 1 through March 31.

You have the chance to get other coverage

• If you can enroll in an employer- or union-sponsored plan, you can drop your Part D or MA plan whenever your employer permits coverage changes.
• If you have or are enrolling in comparable drug coverage (such as VA or TRICARE) you may drop your MA or Part D plan at any time.
• If you enrolled in a PACE plan, you may drop your MA or Part D plan at any time.

Please see our article on creditable coverage for full details.

Your plan’s Medicare contract changes

• If your plan has an issue that causes Medicare to take official action against it, you can switch to another MA or Part D plan, with Medicare determining when you may make that change.
• If Medicare terminates your plan’s contract, the window to change your MA or drug plan opens two months before termination and ends one month after the contract ends.
• If Medicare doesn’t renew your plan’s contract, your window to join another plan runs from December 8 to the last day of February.

Other special circumstances

Medicare recognizes other miscellaneous circumstances that qualify for changes to your Medicare Advantage or Part D plans.

• If you are eligible for both Medicare and Medicaid, you may join, switch, or drop your MA or drug plan at any time.
• If you qualify for Extra Help, you may join, switch, or drop your MA or drug plan at any time. Coverage begins the first day of the month after you qualify for Extra Help and submit your request.
• If you enroll in SPAP (State Pharmaceutical Assistance Program) or lose SPAP eligibility, you may join a drug or Advantage plan once during a calendar year.
• If you canceled your Medigap policy the first time you enrolled in an MA plan, you may drop your Advantage plan to enroll in Original Medicare within 12 months of joining MA for the first time. You also have special rights for buying a Medigap policy.
• If there is a Medicare Chronic Care Special Needs Plan (SNP) available that serves people with your severe or disabling condition, you may join that SNP at any time. However, once you join, you cannot make further changes using this SEP.
• If you are enrolled in an SNP and no longer have a qualifying condition, your window to change to an MA or drug plan lasts for three months, starting with the time you lose your special needs status.
• If your decision to join or not join a plan was due to an error by a federal employee, you have two months from the time you discover or are notified of the error to join, switch, or drop your current plan.
• If you did not receive proper notification that your private drug coverage is not as good as Medicare coverage, you may join either a Part D plan or a Medicare Advantage plan that includes drug coverage for two months after receiving notice of the error.
• If you did not receive proper notification that you were losing creditable drug coverage, you may join an MA plan with drug coverage or a Part D plan for two months after receiving notification of the error.