The project manager should support the decision made by the management and assist engineer A in transitioning into the new role. This includes providing the necessary training and resources to ensure engineer A is successful. Additionally, it's important to keep engineer B motivated and engaged, as their contributions are still valuable to the project. This approach aligns with the PMP objectives of promoting collaboration, supporting team development, and maintaining a productive team environment.
References: = This answer is verified by the principles outlined in the PMBOKGuide, which emphasizes the importance of team development and management's role in project success1. Furthermore, the Professional in Business Analysis materials support the idea of fostering team skills and maintaining team morale2.