Categories - How to change the name of a category

This is not so easy to do, but it is possible.

1. Go to that Old Category page
2. Open ALL the pages and subcategories listed there
3. Add the New Category to ALL these pages, and delete the Old Category there
4. Go back to the Old Category page and refresh
5. Check if there was information on that page that someone wrote there to describe the category. If so, bring this information over to the new Category page
6. Also check if the Old Category is a subcategory of other categories. If so, make sure that you make the New Category a subcategory of the same other categories.
7. Refresh the Old Category page again. If it has no content anymore, you can now delete this page.