Can we end date the existing categories in Manage Functional Area catalog

Can we end-date existing categories that have open POs and invoices associated with them? If we do, what impact will it have on the open POs and invoices?

We’ve updated the categories to "Do Not Use" (DNU), but they still appear when creating Purchase Requisitions (PRs). We want to prevent DNU categories from showing up during PR creation. What will happen if we end-date these categories?