Why Part 43 Matters

Contract modifications are the mechanism for adjusting scope, price, schedule, and terms throughout contract performance. The distinction between bilateral and unilateral modifications affects contractor rights — Changes clause modifications give the contractor the right to an equitable adjustment. Constructive changes (government actions equivalent to a formal change order) are a significant source of claims. Proper modification documentation and pricing are critical for audit compliance.

Key Topics in Part 43

FAR Part 43 addresses several critical areas of the federal acquisition process. Understanding these topics is essential for both contracting officers and contractors working within this regulatory framework.

• Bilateral modifications (supplemental agreements)
• Unilateral modifications and administrative changes
• Changes clause and equitable adjustments
• Constructive changes doctrine
• Standard Form 30 requirements
• Modification pricing and negotiation
• Change order accounting

How FAR Part 43 Applies

The Federal Acquisition Regulation is organized into 53 parts, each covering a distinct area of the procurement process. Part 43 (Contract Modifications) is part of this framework and works in conjunction with other FAR parts to create a comprehensive regulatory structure. Contracting officers must comply with all applicable parts when executing procurement actions, and contractors must understand the requirements that flow from these regulations into their contracts.

The requirements in Part 43 may be implemented through specific contract clauses prescribed in FAR Part 52. When a clause references Part 43, the substantive requirements originate here, while Part 52 provides the actual clause language incorporated into contracts and solicitations.

Subparts

FAR Part 43 is divided into 3 subparts, each addressing a specific aspect of contract modifications.

• 43.1 — General
• 43.2 — Change Orders
• 43.3 — Forms

Reading FAR Part 43

The full text of FAR Part 43 is available on the Electronic Code of Federal Regulations (eCFR). The eCFR provides the most current version of the regulation, including any recent amendments published through Federal Acquisition Circulars (FACs). For historical versions, use the eCFR's point-in-time search feature.

• What does FAR Part 43 cover?

  FAR Part 43 covers contract modifications within the federal acquisition process. FAR Part 43 establishes policies and procedures for preparing and processing contract modifications. It distinguishes between bilateral modifications (supplemental agreements signed by both parties) and unilateral modifications (signed only by the contracting officer). Unilateral modifications include administrative changes and changes issued under the Changes clause (FAR 52.243). The part prescribes Standard Form 30 for contract modifications.

• Who must comply with FAR Part 43?

  FAR Part 43 applies to all executive branch agencies conducting acquisitions, unless a specific exemption exists. Contractors must comply with the requirements that are incorporated into their contracts through prescribed clauses from FAR Part 52. Agency-specific supplements (DFARS, GSAM, etc.) may add additional requirements beyond the base FAR.

• Where can I read the full text of FAR Part 43?

  The full text is available on the Electronic Code of Federal Regulations (eCFR). You can also access it through acquisition.gov, which is maintained by the General Services Administration. Both sources reflect the most current version of the regulation.

• How does FAR Part 43 relate to contract clauses?

  FAR Part 43 establishes the substantive policies and procedures. The actual clause language that gets incorporated into contracts is found in FAR Part 52. Each clause in Part 52 includes a "prescription" that references the relevant policy part, creating a direct link between the requirement and its implementation in the contract.