Final answer:
Jack may not be able to switch to Medigap Plan G without going through underwriting unless he qualifies for specific guaranteed issue rights due to circumstances like his plan being discontinued or moving out of the plan's service area.
Step-by-step explanation:
If Jack started Original Medicare Part A and B on April 1st, 2015, and later enrolled in a MAPD (Medicare Advantage Plan with Prescription Drug coverage), he would have had an initial enrollment period to join a Medigap plan without going through underwriting. This period lasts for six months from the time he was both age 65 or older and enrolled in Medicare Part B. Since he wants to switch to a Medigap Plan G on May 15th, 2016 and avoid underwriting, he may not qualify for the guaranteed issue rights that are typically associated with Medigap open enrollment periods.
Outside the initial enrollment period, applicants are generally subject to medical underwriting unless they have guaranteed issue rights as a result of specific circumstances, such as if their Medicare Advantage Plan is discontinued or they move out of the plan's service area.
To assist Jack, you would need to check if he qualifies for any special circumstances that would grant him guaranteed issue rights. If not, he would likely have to go through medical underwriting to switch from his MAPD to Medigap Plan G.