The Commissioner of the Fiscal Service may waive or modify any provision or provisions of the regulations in this part. He or she may do so in any particular case or class of cases for the convenience of the United States or in order to relieve any person or persons of unnecessary hardship:

(a) If such action would not be inconsistent with law or equity;

(b) If it does not impair any material existing rights; and

(c) If he or she is satisfied that such action would not subject the United States to any substantial expense or liability.

The Commissioner of the Fiscal Service may require:

(a) Such additional evidence to support a requested action as he or she may consider necessary or advisable; or

(b) A bond of indemnity, with or without surety, in any case in which he or she may consider such a bond necessary for the protection of the interests of the United States.

The Secretary may at any time, or from time to time, prescribe additional, supplemental, amendatory, or revised rules and regulations governing retirement savings bonds.