For someone to be eligible to enroll in Medigap Plan policies, he or she must already be enrolled in Original Medicare Part A and Part B and live in the plan’s network.
The best time for an eligible beneficiary to sign up for Medigap Plan D policy is during the six-month Medigap Open Enrollment Period.
During this period, you have the guaranteed issue right to enroll in a Plan D policy of your choice, which means companies may not use medical underwriting to deny you coverage.
If you have End-Stage Renal Disease, you may only enroll in Plan D policies during this six-month period, or else you will be subject to medical underwriting and may be denied coverage because of pre-existing conditions.