38 U.S.C. § 5108: Supplemental claims

(a) In General.—If new and relevant evidence is presented or secured with respect to a supplemental claim, the Secretary shall readjudicate the claim taking into consideration all of the evidence of record. (b) Duty to Assist.—(1) If a claimant, in connection with a supplemental claim, reasonably identifies existing records, whether or not in the custody of a Federal department or agency, the Secretary shall assist the claimant in obtaining the records in accordance with section 5103A of this title. (2) Assistance under paragraph (1) shall not be predicated upon a finding that new and relevant evidence has been presented or secured.