D.C. Mun. Regs. tit. 27, r. 27-3699
When used in this chapter, the following terms and phrases shall have the meanings ascribed:
Amendment - any change to a solicitation issued by the contracting officer.
Bilateral contract modification - a contract modification that is signed by the contractor and the contracting officer.
Change order - a written order signed by the contracting officer directing the contractor to make a change that the contracting officer is authorized to order without the contractor's consent pursuant to the contract.
Contract modification - any written change in the terms of a contract.
Supplemental agreement - a bilateral contract modification.
Unilateral modification - a contract modification that is signed only by the contracting officer.
D.C. Mun. Regs. tit. 27, r. 27-3699