D.C. Mun. Regs. tit. 8, r. 8-A1205
An employee may be temporarily detailed to perform duties which are separate and distinct from those regularly assigned, including the performance of duties normally assigned to another position which has become temporarily vacant.
During a period of detail, an employee shall continue to encumber the position from which he or she is detailed. A vacant position shall not be deemed filled by detail.
Except as provided otherwise under § 1108 of this title, an employee's rights and pay shall remain based on the official assignment, not on the duties or job to which he or she is detailed.
An employee may be detailed on an informal basis for up to thirty (30) days, or officially detailed by written directive approved by the Dean for a period not to exceed one hundred twenty (120) days.
D.C. Mun. Regs. tit. 8, r. 8-A1205