20 C.F.R. § 219.4

(a) Claimant or representative responsible. When evidence is required to prove a person's eligibility for or right to continue to receive annuity or lump-sum payments, that claimant or his or her representative is responsible for obtaining and submitting the evidence to the Board.

(b) What to do when required evidence will be delayed. When the required evidence cannot be furnished within the specified time, the claimant or representative who was asked to furnish the evidence or information should notify the Board and explain why there will be a delay. If the delay is caused by illness, failure to receive the information from another source, or a similar situation, the claimant will be allowed a reasonable time to secure the evidence or information. If the information is not received within a reasonable time as determined by the Board, the claimant or representative who was asked to furnish the evidence or information will be notified of the effect that his or her failure to furnish the evidence or information will have on the claimant's eligibility to receive or continue to receive payments.