42 CFR § 411.126
Reopening of determinations and decisions
June 11, 2020
(a) A determination that a GHP or LGHP is a nonconforming GHP or the decision or revised decision of a hearing officer or of the CMS Administrator may be reopened within 12 months from the date on the notice of determination or decision or revised decision, for any reason by the entity that issued the determination or decision.
(b) The decision to reopen or not to reopen is not appealable.