[color=#00CC00]Panel > Domains > Manage Domains[/color]
Next to your domain, click Edit (under Web Hosting)
FTP user / CGI-runs-as user: Select the new user here
Copy domain's files to new user? [color=#00CC00]Checked[/color]
Click [color=#0000CC]Change fully hosted settings now![/color]
The current website files will be copied over to the newly selected user and from now on that user has full control over the domain. You'll still have an "old" domain.com folder at the original user, so it's a good idea to remove it to avoid any future confusion.
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