What FAR Part 43 - Contract Modifications (Bilateral, Unilateral, Change Orders, Constructive Changes) requires
Federal Acquisition Regulation (FAR) Part 43 governs modifications to federal contracts and prescribes the only authorities by which the Government may alter a contract: Subpart 43.1 defines bilateral modifications (signed by both contractor and contracting officer - used for negotiated equitable adjustments, definitization of letter contracts, and other agreements) and unilateral modifications (signed only by contracting officer - used for administrative changes, change orders, and other authorised modifications); FAR 43.102 establishes that only contracting officers with proper authority may execute contract modifications - other Government personnel must not direct contractors to perform work requiring a modification (preventing the constructive change doctrine from being weaponised by uncoordinated agency personnel); 43.103 categorises modifications and 43.201 prescribes change order authority through the standard Changes clauses (52.243-1 fixed-price supplies, 52.243-2 cost-reimbursement, 52.243-3 time-and-materials, 52.243-4 construction with consolidated change procedures); 43.204 requires the contracting officer to negotiate equitable adjustments in the shortest practicable time considering segregable costs and including complete releases to prevent future disputes; 43.205 prescribes the mandatory changes clauses; 43.301 mandates Standard Form 30 (SF 30) for solicitation amendments, change orders, unilateral contract modifications, administrative changes, supplemental agreements, and fund adjustments. Constructive changes - actions by Government personnel that direct work beyond contract scope without a formal modification - give rise to constructive change claims under the Changes clause.
Pillar: Public Sector & Government Procurement · Authority: Federal Acquisition Regulatory Council (DOD, GSA, NASA) issuing the Federal Acquisition Regulation under 41 USC 1303 and 48 CFR Chapter 1 · Version: 1.0.0 · Last updated:
Primary source: https://www.acquisition.gov/far/part-43
SHA-256 integrity: 8752c8a6e86cf4381346816d468808b07df45f0ff8449ab2a9bbd63069137640
Primary Citations — 6 traced to source
- FAR Part 43 Section 43.101 (Definitions): 'Bilateral modification (supplemental agreement) is a contract modification that is signed by the contractor and the contracting officer. Bilateral modifications are used to (1) Make negotiated equitable adjustments resulting from the issuance of a change order; (2) Definitize letter contracts; and (3) Reflect other agreements of the parties modifying the terms of contracts. Unilateral modification is a contract modification that is signed only by the contracting officer. Unilateral modifications are used, for example, to (1) Make administrative changes; (2) Issue change orders; (3) Make changes authorized by clauses other than a changes clause...and (4) Issue termination notices.'
- FAR Part 43 Section 43.102(a) (Policy): 'Only contracting officers acting within the scope of their authority are empowered to execute contract modifications on behalf of the Government. Other Government personnel shall not (1) Execute contract modifications; (2) Act in such a manner as to cause the contractor to believe that they have authority to bind the Government; or (3) Direct or encourage the contractor to perform work that should be the subject of a contract modification.'
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