D.C. Mun. Regs. r. 27-3600
Only a contracting officer acting within the scope of the contracting officer's delegated contract authority is authorized to execute a contract modification on behalf of the District. Other District personnel shall not:
A contract modification, including a change issued unilaterally by the District, shall be priced and a government estimate shall be prepared before signature by the parties, unless the interest of the District would be adversely affected. If a significant cost increase could result from a contract modification and time does not permit negotiation of a price, the contracting officer shall negotiate a maximum contract price increase and include that price in the modification.
The contracting officer shall not execute a contract modification, including a change order, which causes or will cause an increase in the funding level of the contract without having first obtained a certification of the availability of funds. The certification shall be based on the negotiated price or the negotiated maximum price.
A modification to a contract may be executed without having first obtained the certification required under § 3600.3 if the modification includes a clause, approved by the Director, which conditions payment upon the availability of funds.
D.C. Mun. Regs. r. 27-3600