D.C. Mun. Regs. tit. 14, r. 14-1933
The housing provider shall be eligible for assistance payments for a tenant through the end of the calendar month in which the tenant vacates the unit without required notice. The tenant shall notify DCHA when the tenant plans to vacate the unit. If the tenant vacates without notice, the housing provider shall notify DCHA within ten (10) calendar days of the vacancy.
If the vacated unit is reoccupied that same month by another tenant assisted under the Tenant Assistance Program, DCHA shall credit the previously paid assistance for that unit for that month, on a daily pro-rata basis, to the assistance due the housing provider for the new tenant. However, if the new tenant's level of assistance is below that of the moved-out tenant, the housing provider shall not be liable for the difference.
D.C. Mun. Regs. tit. 14, r. 14-1933