Which of the following is a written agreement between the owner and contractor to change the contract?

A change order is a formal written agreement between the owner and the contractor that modifies the original construction contract. It specifically outlines changes in the work to be performed, adjustments in the contract sum, and amendments to the contract timeline. Change orders are essential in construction project management as they document changes that may arise during the project, ensuring that both parties agree to any modifications and providing clear communication.

In practice, change orders can arise due to various reasons such as unforeseen conditions, design changes, or client-requested modifications. By officially documenting these changes, both the owner and contractor maintain clarity regarding obligations, costs, and schedules, thereby helping to minimize disputes.

Other options, while also related to contractual changes, differ in their specific usage and implications. A contract amendment typically refers to changes made directly to the terms of the original contract rather than to specific work items. A supplemental agreement might address additional work or terms not covered by the original contract, and a notice of change often serves as an initial notification of a change rather than a formal agreement. Thus, the specific nature and function of a change order make it the most accurate answer to the question.