5 C.F.R. § 880.204 – Restoration of annuity.

(a) If the missing annuitant's whereabouts are determined, and he or she is alive and—
1. (1) Competent, OPM will resume payments to the annuitant and pay retroactive annuity for the period in missing status less any payment made to the family during that period; or
2. (2) Incompetent, OPM will resume payments to a representative payee under section 8345(e) or section 8466(c) of title 5, United States Code, and pay retroactive annuity for the period in missing status less any payment made to the family during that period.
(b) If the missing annuitant's whereabouts cannot be determined, missing annuitant status continues until an authorized institution determines that the missing annuitant is dead. (See § 880.205.)