5 U.S. Code § 6365 - Contributions of annual leave
Contributions of annual leave
Upon approving an application under subsection (a), the employing agency of the leave contributor may transfer all or any part of the number of hours requested for transfer, except that the number of hours so transferred may not exceed the limitations under paragraph (2).
A leave contributor who is projected to have annual leave that otherwise would be subject to forfeiture at the end of the leave year under section 6304(a) may contribute no more than the number of hours remaining in the leave year (as of the date of the contribution) for which the leave contributor is scheduled to work and receive pay.
The Office of Personnel Management shall prescribe regulations establishing an open enrollment period during which an employee may contribute leave under subsection (a) for a leave year.