Help migrating a virtualmin site to a subdomain on another server

I have two websites, both running on virtualmin (centOS & apache) but on different servers: domain1.com & domain2.com. domain2.com has expired and is not really worth renewing, so I want to move it to a subdomain on the other server d2.domain1.com. I’m trying to avoid migrating the db & files so I thought I could manage this with the alias feature in Virtualmin. Can someone please help me with the steps involved (change DNS, set up aliases, etc)? I’ve tried some things but it’s not working as I’d expected.

This is the best way to do it:

Virtualmin → Server Configuration → Change Domain Name.
Just change the domain name to the sub domain here

Yes, keep the subdomain as a top level virtual server. That’s the better and simpler way to do it.

Excellent that should work fine. Thanks a lot. What about the DNS changes? Surely I have to do something on domain1.com to have the new subdomain resolve to the correct server?