Deleting event categories
Since your church's Calendar module events (past, present and future) are always linked to a Category, deleting a Category would delete all events associated with that Category.
To avoid loss of data (including event sign-ups, tickets, ticket payments, etc), when deleting a category, the user is prompted to select (or create) an alternative category for associated events to be transferred to - perhaps an "Archived Events" category.
A series of warnings prevent accidental deletion of Categories without reassignment of associated events.
Importantly, you must create the alternative category before running the "delete category" process; since you are required to select the alternative category from the above drop-down list.
Once you have confirmed, click "Delete Category". ChurchSuite will re-assign all associated events (and linked data) to the new category before finally deleting the old category.