I feel that this is an important feature to have automated to switch an ip domain to ipless and an ipless domain back to ip...
Should be done from the Modify An Account in WebHost Manager or a command line script.
Currently the only way to do it automatically is to remove the account and than re-adding it which of course would cause that user to loose all their settings/and home directory.
It should update the nameserver and all associated files (httpd.conf, etc).