The Changing Role of the PM Over Course of Project
Project management is dynamic, and in no way more than the way it changes over the course of the project.
Different phases of projects require different attention. If you have your PMP, you are well aware of that!
The transitions, also, include overlaps and gray areas.
But one area for special attention is that of the team. Team dynamics also changes as the project progresses.
I read and excellent article on the changing role of the PM as team leader during the project. Rather than project phase-centric, it is team dynamics-centric.
Clarity and awareness of this can remove a lot of stress from the project, enabling proper focus on the most productive things.
One more comment: I think this model can somehow also be extended to the "greater project team" to include the full array of stakeholders, albeit with some different dynamics. For example, stakeholders that are intimately involved with the project would probably follow a similar pattern, but others may come in and out of the mix depending on the stage of the project.
See Five Stages of Team Development and the Role of the Project Manager by Gina Abudi.