PMP Certification Executing Questions Test 6

Very late into project execution, the project manager realizes that the materials supplier specified in the project quality documents has gone out of business. The only other alternative for that exact material specification is located overseas, which will extend the delivery lead times and significantly impact the project budget.
However, there is an alternative material that is locally manufactured. While the specifications are different, the material will meet project requirements.
What must the project manager implement before acquiring the alternative material?