During project execution, a key team member has to be moved to another critical project...

 According to the PMP Exam Content Outline, one of the tasks of the project manager is to “Assess and prioritize impact on project scope, schedule, cost, quality, and risks of approved changes, and determine cause and effect relationships” (Task 5, Domain II: Process). This implies that the project manager should evaluate the impact of any change that affects the project performance, such as the removal of a key team member. By doing so, the project manager can identify the potential consequences and benefits of the change, and look for alternatives to mitigate the negative effects or enhance the positive ones. The project manager should also submit a change request if required, to update the project management plan and baselines accordingly. This will help to maintain the project alignment with the objectives and expectations of the stakeholders. References:

PMP Exam Content Outline, Domain II: Process, Task 5, page 101

PBA Exam Content Outline, Domain IV: Evaluation, Task 4, page 152

A Guide to the Project Management Body of Knowledge (PMBOK Guide), Sixth Edition, Chapter 4: Project Integration Management, Section 4.6: Perform Integrated Change Control, page 1233

Business Analysis for Practitioners: A Practice Guide, Chapter 6: Traceability and Monitoring, Section 6.4: Manage Changes to Requirements, page 117