Which is a purpose of the ‘controlling stage’ process?

[Reference: https://publications.axelos.com/PRINCE2Agile2016/content.aspx?page=pra_117&showNav=true&expandNav=true#:~:text=The%20purpose%20of%20the%20Controlling,the%20stage, %20remains%20within%20tolerance.&text=Risks%20and%20issues%20are%20kept%20under%20control, ]