How to edit main domain of an account

In cPanel, one can change the main domain of any account by using the edit function. Easy and simple. in CWPpro, when you Edit Account, there is no way to change the Main Domain. I want just to make an addon domain, pointing to the root directory, to make it main domain, i.e., to replace the current main domain with the name of a parked domain, keeping the path to the root directory unchanged.

I think you would have to delete the parked domain, then create a new user with the parked domain as the main domain, and then move any content of the /home/olduser/public_html to the new public_html, as well as any databases (export, then import under the new mysql user). Slightly cumbersome, but in actuality accomplished within minutes.