APEX
Terminate an Account
Steps
1 To access the Account Functions Menu, click on Account Functions, on the main screen of your WebHost Manager interface.
2 Click on Terminate an Account.
3 Click on the domain name of the account you wish to delete.
4 If you wish to keep the DNS zone for this account, click on the box next to Keep DNS Zone.
5 Click on Terminate to delete the account.
You can delete all the accounts that a user owns by clicking on their user name rather than the domain name of the account you wish to delete.
Очень неплохая документация по этой панели, правда на английском языке:
http://www.cpanel.net/docs/whm/