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Acronymsaka: change order requestaka: change order proposalaka: COP

COR (Change Order Request)

In Plain English

A formal request from a contractor asking for more money or time because something changed on the project.

Definition

A Change Order Request is a formal document initiated by a contractor to request a change in the contract's scope, price, or schedule in response to an owner-directed change, unforeseen condition, or design revision. The COR documents the proposed cost impact and schedule adjustment and is submitted to the owner or owner's representative for review and approval. Once approved and signed by both parties, the COR is incorporated into a formal change order that amends the contract.

Why It Matters in Bidding

A timely, well-documented COR is how a contractor protects cash flow and recovers cost when scope grows, so the estimating and project teams must price extra work with the same rigor as the base bid, including markup, equipment, and schedule impact. Weak or late CORs get disputed or denied, meaning the contractor performs added work at its own expense, which is why notice timing and backup documentation are critical.

Example

After uncovering buried debris during excavation, the superintendent stops work, and the estimator prepares a COR detailing added labor, hauling, and two days of schedule impact for the owner's review before crews proceed.

Related Terms

PCO (Potential Change Order)RFI (Request for Information)WBS (Work Breakdown Structure)

Frequently Asked Questions

A COR is the contractor's request proposing the cost and time impact of a change; it is not yet binding. A change order is the executed document, signed by both parties, that actually amends the contract sum and schedule. Work directed but not yet covered by a signed change order leaves the contractor exposed to nonpayment.
A strong COR includes a detailed cost breakdown of labor, material, equipment, and markup, the schedule impact, and references to the directive or condition triggering it, such as an RFI, field directive, or differing site condition. Photos, daily reports, and quotes strengthen it. Thorough backup speeds approval and withstands the owner's review or audit.
Performing changed work before approval risks nonpayment, so contractors generally should not proceed without written authorization. When schedule pressure forces action, many contracts allow a written construction change directive or time-and-materials authorization to start work while pricing is finalized. Documenting actual costs daily during such work is essential to later justify the amount.

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