The project plan is used by the project board to monitor the project's progress.
The project plan is updated to incorporate actual progress from the stage that is finishing, and includes a forecast duration and costs from the exception plan or stage plan for the stage about the begin. The business case also gets updated with revised costs or end dates.
PRINCE2 recommends the following actions:
✔ Check that the current stage plan is up to date with actual progress and update if needed
✔ Revise the project plan
✔ Update the issues register and risk register if any new issues or risks have been identified
