Shared
Unfortunately, you may not change the user name associated with your control panel. Once it is set, there are vital components using that name. Some of those settings are used by your web site, and are not controlled by HostMop.
Reseller
You may change the user names for any accounts you create, but you cannot change the user name you suggested during sign up.
VPS and Dedicated
You may change the user names for any accounts you create, but you cannot change the user name provided by HostMop; Linux is always root, and Windows is always admin.
If you need to change your main domain name, we need to charge you administrative fee USD 6