Question
How do I merge two cPanel accounts?
Answer
The cPanel Software has functionality to perform the opposite, which is to convert an Addon Domain into its own account. There is a feature request at the following page for such functionality to be implemented into the cPanel software here:
https://features.cpanel.net/topic/convert-cpanel-account-to-addon-domain
We also have some details on how to merge two cPanel accounts here if need be:
https://forums.cpanel.net/resources/how-to-manually-combine-two-cpanel-accounts-into-one.635/
There are various warnings on this page to take note of, so please keep those warnings in mind before attempting to perform such changes. They are best performed by a Server Administrator who is well versed in bash at the root level.