Senior Resources » Does Enrolling in a Medicare Supplement Cancel a Medicare Advantage Plan?

Does Enrolling in a Medicare Supplement Cancel a Medicare Advantage Plan?

senior woman saying uh oh on the phone in front of her computer talking about medicare supplement



Last year during Medicare’s Annual Enrollment, both my husband and I qualified for a Medicare Supplement Plan G over the phone from a telemarketing call. The supplement has never paid a dime! We still must use the same doctor and get referrals from our Medicare Advantage HMO. We can’t get the Medicare Supplement to pay because no one advised us how to stop the Medicare Advantage plan.

We have spent over $250 a month since January and the Medicare Supplement Plan G has never been used. How can we get out of this Medicare Advantage plan and return to Original Medicare to use the Medicare Supplement purchased last November?


Looking forward to your answer, Toni.

Laura from Tampa, Fla.

Hello Laura,

The biggest no-no in the Medicare insurance world occurs when an insurance company or agent sells a new Medicare Supplement to a Medicare beneficiary (which includes you and your husband) with a Medicare Advantage plan without properly advising the client on how to properly disenroll from their current Medicare Advantage plan.

Medicare enrollment written on a notepad with pen

Laura, as you are now finding out, because the agent who sold you the Medicare Supplement failed to inform you and your husband how to disenroll properly from your Medicare Advantage plan, you and your husband have not been in Original Medicare for the last year and could not use the Medicare Supplement benefits you are paying for. 

The change would have been a simple one because you both qualified medically for the new Medicare Supplement. All the agent needed to do was enroll you and your husband in a standalone Medicare Part D prescription drug plan. This simple step would have canceled your Medicare Advantage HMO Plan effective January 1 and returned you and your husband to Original Medicare with a Medicare Supplement and a new Medicare Part D prescription drug plan.

You need to enroll in the standalone Medicare Part D plan that covers you and your husband’s current prescription drugs as soon as possible or no later than midnight December 7th or you will remain in the same situation that you are in right now, Laura.

Readers, this is what the Medicare Annual Enrollment Period (AEP) from October 15 to December 7 is all about! It’s the time to enroll in a new Medicare Part D prescription drug plan or Medicare Advantage plan (chapter 6 of Toni’s Medicare Survival Guide Advanced Edition explains Medicare’s AEP rules in detail).

medicare supplement

If you are changing to a Medicare Supplement, you need to have passed the medical underwriting process and be approved for the Medicare Supplement before enrolling in a standalone Part D plan, which will automatically cancel your Medicare Advantage Plan. If you are not approved for a Medicare Supplement before you sign up for Part D and you miss the December 7th deadline, all costs that Original Medicare does not pay will become your financial responsibility without a Medicare Supplement. 


Insurance agents who are properly trained regarding Medicare Advantage rules know that those enrolled in Medicare Advantage plans should enroll in a standalone Medicare Part D plan by midnight December 7th to be disenrolled properly from a Medicare Advantage plan once the Medicare Supplement is approved. 

Most Americans do not realize that they cannot have both Original Medicare and a Medicare Advantage plan at the same time. Medicare will pay the Medicare Advantage plan for your care. Original Medicare and a Medicare Advantage plan cannot pay at the same time. Confusing… I know! Remember – with Medicare, it’s what you DON’T know that will HURT YOU!

Have a Medicare question, call Toni Says at (832) 519-8664 or email Toni’s books are available for purchase at with a special bundle discount for Toni Says® readers.

Originally published November 15, 2023

Free Senior Resources

Baby Boomers' Guide to Facebook

Baby Boomers’ Guide to Facebook

Get The Guide
Blessings for Baby Boomers

Blessings for Baby Boomers

Get The Guide
Ultimate Estate Planning Checklist and Guide, 2023

Ultimate Estate Planning Checklist & Guide

Get The Guide
Medicare Guide for Veterans cover

Medicare Guide for Veterans

Get The Guide
Show this content while the ad loads.