how to change the user's domain

[ender049]

I find there is not any way to change the user's domain in GUI.
For example:
I add a user which domain is hisdomain.tld.
but after some day,he want to change his domain too newdomain.tld.
what should I do ?

[kilburn]

Create the new domain, transfer web files/databases, remove the old domain.

[ender049]

there is not other way?
transfer web files/datebases seems troublesomely