Hello Worldonfire,
In order to transfer a domain from one account to another, it cannot be a primary domain name. If that is the case, you will first want to do a primary domain name change to swap it with an addon domain.
Once the domain you want to move is set as an addon, you will want to remove it from the addon list on its original account. You can do that by simply visiting the Addon Domain tool found in the Domains category of the cpanel and clicking the Remove link found on the right hand side. This removes it from the original account.
Then all you need is to add the domain as an addon in the new account.
That is all there is to it!
I hope that answers your question today. If you ahve any further questions about that please leave a comment below.
Thank you!
- Scott M