According to the PMP Exam Content Outline, one of the tasks of the project manager is to "Manage project team members by negotiating and influencing their assignments, providing feedback, resolving and escalating issues, and managing team development" (Task 9, Domain II: Process). This implies that the project manager should protect the project team from any external interference or distraction that could affect their performance or availability. The project manager should also respect the contractual agreements and scope boundaries of the project, and avoid any unauthorized work or scope creep. Therefore, the project manager should decline the request politely since the issue is unrelated to the project and is not the responsibility of the project team.
The project manager should also direct the customer to the appropriate channel or department to handle their request, such as the sales manager or the customer service team. References:
* PMP Exam Content Outline, Domain II: Process, Task 9, page 101
* PBA Exam Content Outline, Domain III: Analysis, Task 7, page 132
* A Guide to the Project Management Body of Knowledge (PMBOK Guide), Sixth Edition, Chapter 9:
Project Resource Management, Section 9.4: Manage Team, page 3413
* Business Analysis for Practitioners: A Practice Guide, Chapter 5: Requirements Life Cycle Management, Section 5.3: Manage Requirements Traceability, page 97