According to the PMBOK Guide, when a change request is received, the project manager should evaluate the impact of the change on the project scope, schedule, cost, quality, risk, and other aspects. The project manager should also consult with the project sponsor and other key stakeholders to obtain their approval or rejection of the change request. The project manager should not proceed with the change without proper analysis and authorization, nor should they reject the change without considering the legal and contractual implications. References: PMBOK Guide, 6th edition, pages 115-116, 134-135, 141-142.