A vendor informed the project manager that a critical resource will be on a long...

 Perform Integrated Change Control is the process of reviewing all change requests, approving changes and managing changes to deliverables, organizational process assets, project documents, and the Project Management Plan, and communicating the decisions1. This process is important to ensure that only approved changes are implemented and that the project remains aligned with the project objectives and stakeholder expectations. In this scenario, the project manager should perform Integrated Change Control to evaluate the impact of the proposed alternative solution on the project scope, schedule, cost, quality, risk, and other aspects. The project manager should also consult with the project sponsor, customer, and other key stakeholders to obtain their approval or rejection of the change request. The project manager should document the change request and its status in the change log and update the project management plan and other relevant documents accordingly. The project manager should also communicate the change and its implications to the project team and other affected parties. By performing Integrated Change Control, the project manager can ensure that the project is managed in a controlled and consistent manner, and that the project deliverables meet the agreed requirements and expectations. References:

How To Successfully Perform Integrated Change Control

6 Steps for an Integrated Change Control Project Management Strategy

Performing Integrated Change Control: PMP Tips