The Managing a Stage Boundary process provides the Project Board with information necessary to review the success of the current stage and decide whether there remains a justified business reason to continue with the project. This process includes the evaluation of the stage's performance and the ongoing viability of the project. References: PRINCE2 Foundation Training Manual; PRINCE2 2017 Foundation handbook.

An objective of the 'Controlling a Stage' process in PRINCE2 is to replan the current stage when directed.
This process handles day-to-day management of the project, and includes responding to issues that might impact the stage plan, requiring replanning to ensure project objectives can still be met.
PRINCE2 Foundation Manual

In PRINCE2, the responsibility for documenting any tailoring of the Business Case theme, along with other themes, generally falls to the Project Manager. This includes documenting how the theme is being applied in a particular project context, ensuring the approach remains appropriate and meets the project's requirements.
PRINCE2 Foundation Manual

Applying the 'tailor to suit the project' principle in PRINCE2 helps make project management less bureaucratic by allowing for adaptations based on the project's size, complexity, environment, and stakeholders' needs. This flexibility reduces unnecessary overhead and ensures that the project management approach is both effective and efficient, enhancing overall project delivery without being overly constrained by rigid processes.
PRINCE2 Foundation Manual

The process that aims to ensure accurate progress information is provided to the Project Manager is Managing Product Delivery. This process is essential for maintaining accurate communication about the status of the work being done, enabling the Project Manager to effectively monitor and control project progress.
References: PRINCE2 Foundation official documentation and study materials.
These responses are crafted based on the latest PRINCE2 Foundation guidelines and documentation, ensuring accuracy and compliance with the standards set by the PRINCE2 methodology.