20 CFR § 349.2 - Conditions for reopening.
A final decision may be reopened:
(a) Within 12 months of the date of the notice of such decision, for any reason;
(b) Within four years of the date of the notice of such decision:
(1) If there is new and material evidence; or
(2) If the decision was not reasonably consistent with the evidence of record at the time of adjudication.
(c) At any time if:
(1) The decision was obtained by fraud or similar fault;
(2) The decision was that the claimant was not a qualified employee, and he or she is now qualified because compensation was credited to the employee's record of compensation in accordance with part 211 of this chapter:
(i) To correct errors apparent on the face of the compensation record;
(ii) To enter items transferred by the Social Security Administration which were credited under the Social Security Act when they should have been credited to the employee's railroad retirement compensation record; or
(iii) To correct errors made in the allocation of earnings to individuals or periods which would have made him or her a qualified employee at the time of the decision if the earnings had been credited to his or her earnings record at that time;
(3) The decision is wholly or partially unfavorable to a claimant, but only to correct a clerical error or an error that appears on the face of the evidence that was considered when the decision was made.