Hello,
When you create a backup with directadmin of admin's account it will be named as:
admin.root.admin.tar.gz
So you need to rename it to:
user.admin.userbob.tar.gz
you can change:
admin to any other reseller's name you actually use on the server.
userbob to any other name for the user account.
as soon as you rename the archive and copy it to a target server restore it via directadmin.
You will need to adjust PHP scripts as MySQL DBs will change their names.