You may run into a scenario where a user wants to convert an add-on to have it's own separate cPanel account. To do that, search for "convert" in the WHM seach bar to find the Convert Addon Domain to Account option:
The interface lists all add-on domains on your server and you can search for the one you would like converted to a cPanel account and who its owned by.
Clicking Convert will allow you to choose a new owner for the account and hosting plan associated with it.
The tool should automatically detect if there are any MySQL databases, Email address, FTP users, or any other data that should be moved. Once you’ve confirmed the list is good click Start Conversion to being the process.
How long it takes will very much depend on how much data needs to be migrated. For a single small WP install this should only take a minute or two. Once completed you’ll find the new account in WHM under List Accounts. For DoOO environments you may wish to also setup an order in WHMCS associated with a user who will need cPanel access.