Hello Chris,

AbleCommerce does not have a 'set category' structure. The categories are created by the admin user(s) of the store. You can change the names, remove, and add new ones. If you are using version 9, just make sure you're thinking about the existing URL that might be indexed in a search engine. When changing the category name, there is an option to update the URL and add a redirect.

I've seen some sites that will hard-code the category names in the menu as a customization, so if you're not sure, take a backup of the database first before making any big changes.