If you need to change an addon domain as a standalone cpanel account, follow these steps:
1. Take a full backup of the user from Cpanel
2. Extract the backup onto your PC.
Create as stand alone account
3. Remove that addon domain
4. Create that domain from WHM –> Create new account
Restore web files
5. Copy all web files of that addon domain from the backup to the new document root.
6. Change the ownership all files to newuser.newuser
7. Make sure the name of DB for each domain.
8. In backup directory there is a mysql directory. All DB’s are under that mysql directory.
9. Login to the new cpanel account of that new account.
10. Create a DB, DB user from Cpanel –> Mysql
11. Give all privileges to that mysql user to the corresponding DB from there.
12. Make sure to edit all mysql configuration files in the document root of that domain.
13. Restore the old DB to new DB.
14. In the backup, we can see a directory named mail. Copy the directory of the domain from that directory to new accounts mail directory /home/newuser/mail/
15. Change the ownership of that directory under /home/newuser/mail/ to newuser.newuser
Restore mail accounts with same password
16. In the backup we can see a directory etc. Copy the directory of the domain from that directory to new accounts /home/newuser/etc/
17. Change the ownership of that directory under /home/newuser/etc/ to newuser.mail
That all folks