22 U.S.C. § 3643
The head of any agency may enter into agreements for the transfer or detail to the Commission of any employee of that agency serving under a permanent appointment. Any employee who so transfers or is so detailed shall, upon completion of the employee's tour of duty with the Commission, be entitled to reemployment with the agency from which the employee was transferred or detailed without loss of pay, seniority, or other rights or benefits to which the employee would have been entitled had the employee not been so transferred or been so detailed.
For purposes of this section, the term "agency" means an Executive agency, the United States Postal Service, and the Smithsonian Institution.
The Office of Personnel Management shall prescribe regulations to carry out the purposes of this section.
22 U.S.C. § 3643