Timing is critical when you have decided you want to leave a Medicare Advantage plan. This video contains the detailed steps needed in order to make this happen. They include:
1) Apply for a Medicare Supplement (if you wish to replace the Advantage with a Supplement.)
2) After obtaining approval on the Supplement FIRST –
3) Join a Part D plan. This will trigger the cancelation of the Medicare Advantage Plan
We have those steps, and help to do it, here:

Information current as of November 18, 2020.

leave medicare advantage