22 C.F.R. § 512.24 Non-waiver of rights by payments.
Title 22 - Foreign Relations
An employee's voluntary payment of all or part of a debt being collected under 5 U.S.C. 5514 shall not be construed as a waiver of any rights which the employee may have under 5 U.S.C., or any other provision of contract or law, unless statutory or contractual provisions provide to the contrary.
Title 22: Foreign Relations
PART 512—COLLECTION OF DEBTS UNDER THE DEBT COLLECTION ACT OF 1982
Subpart C—Salary Offset
§ 512.24 Non-waiver of rights by payments.

