A contract is signed the work begins on the project, and the site conditions turn out to be different than expected. As a result the project will cost more than the original estimate. The owner would correct the contract to pay for these unexpected conditions by issuing a?

A contract is signed the work begins on the project, and the site conditions turn out to be different than expected. As a result the project will cost more than the original estimate. The owner would correct the contract to pay for these unexpected conditions by issuing a?