A brewer may change the terms of any bond filed under this part by filing a consent of surety. Consents of surety will be executed on Form 1533 (5000.18) by the brewer and the surety on the bond, with the same formality and proof of authorization as required for the execution of a bond. (Sec. 201, Pub. L. 85-859, 72 Stat. 1388, as amended (26 U.S.C. 5401))