What do I do if I am automatically enrolled in Medicare but want to remain on a group medical insurance plan? If you are drawing Social Security benefits prior to age 65, or not yet age 65 but qualify under the 25 month disability rules, you are automatically enrolled in Part A and B of Medicare. Your red white and blue Medicare card will arrive in your mail about three months prior to your effective date to start receiving Medicare benefits.
If you choose to keep working and are eligible to remain on your employer’s group health plan, you may need to dis-enroll from Part B coverage to avoid an automatic withdrawal for the Part B (Medical) premium from your Social Security check.
Here’s what you do. If you want Part B now, cut out and keep the card. Your coverage and premiums begin on the date shown. 
If you do not want Part B, carefully follow the instructions on the backside of the form. Check the box indicating: I Do Not Want Medical Insurance __ (check here). Sign you name where indicated and return the entire form in the enclosed envelope.
Do not tear off the Medicare card. You must return the form BEFORE the Part B effective date shown on the card.
You still have Part A even though you do not want Part B. The Centers for Medicare and Medicaid services will send you a new card showing that you have Part A only.
