D.C. Mun. Regs. tit. 27, § 3606
3606.1 For a solicitation amendment, change order, or administrative change, the effective date shall be the date on which the contracting officer issues the amendment, change order, or administrative change.
3606.2 For a bilateral modification (supplemental agreement), the effective date shall be the date agreed upon by the contracting officer and the contractor.
SOURCE: Final Rulemaking published at 35 DCR 1688 (February 26, 1988).