The process in which the PID (Project Initiation Documentation) is reviewed and, if necessary, updated to reflect external factors that may affect the delivery and business justification of the project is 'Managing a stage boundary.' During the 'Starting up a project' phase, the PID is not yet created. In the 'Initiating a project' process, the PID is initially developed. 'Controlling a stage' focuses on ensuring that the project remains on track while managing the current stage. 'Managing a stage boundary' is the phase where a project’s performance and progress are evaluated at the end of each stage, and this includes reviewing and updating the PID to reflect any changes or necessary adjustments.