What is one way a contract may be changed or modified?

A change order is a formal document that amends the original contract, detailing changes to the work, adjustments in cost, or modifications to the schedule. This tool is essential in construction projects since it provides a clear method for both parties—the owner and the contractor—to agree on changes to the scope of work once the project is underway. Change orders ensure that all necessary adjustments are documented and that both parties are aware of the implications of these modifications, which helps to prevent disputes.

Other options, while related to construction and project management, do not serve as mechanisms for changing or modifying a contract. An architect's complaint form is typically used for registering grievances regarding an architect’s performance or conduct rather than changing the contract terms. A final design directive may give instructions related to design, but it doesn’t serve as a contractual modification. A request for proposal is a document used to solicit bids for a project and is not intended for contract modification. Thus, the change order stands out as the appropriate instrument for contract changes.