Federal Acquisition Regulation
Types of contract modifications
FAR 43.103
Contract modifications are of the following types: (a) Bilateral. A 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. (b) Unilateral. A 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 (e.g., Property clause, Options clause, or Suspension of Work clause); and (4) Issue termination notices.
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