made by this subsection shall apply to months beginning after December 31, 2018, in taxable years ending after such date. 5. Allowing certain individuals with alternative health coverage to choose to opt out of the Medicare part A benefit (a) In general Any individual described in subsection (c) who is otherwise entitled to benefits under part A of title XVIII of the Social Security Act may elect (in such form and manner as may be specified by the Commissioner of Social Security, in consultation with the Secretary of Health and Human Services) to opt out of such entitlement. Notwithstanding any other provision of law, in the case of an individual who makes such an election, such individual— (1) may (in such form and manner as may be specified by the Commissioner, in consultation with the Secretary) subsequently choose to end such election and opt back into such entitlement (in accordance with a process determined by the Commissioner, in consultation with the Secretary) without, subject to subsection (b), being subject to any penalty