42 CFR §423.668

1. (a)CMS may reopen and revise an initial determination upon its own motion.
2. (b)Contract determination. A decision of a hearing officer that is unfavorable to any party and is otherwise final may be reopened and revised by the hearing officer upon the officer's own motion within 1 year of the notice of the hearing decision. Another hearing officer designated by CMS may reopen and revise the decision if the hearing officer who issued the decision is unavailable.
3. (c)Decision of Administrator. A decision by the Administrator that is otherwise final may be reopened and revised by the Administrator upon the Administrator's own motion within 1 year of the notice of the Administrator's decision.
4. (d)Notices.
   1. (1)The notice of reopening and of any revisions following the reopening is mailed to the parties.
   2. (2)The notice of revision specifies the reasons for revisions.