Change Active Director Domain name

I accidently introduced a NEW NT 4 server named “x” into an environment that already had a W2K Adv Server with a domain name of “x”. Ofcourse the FULL W2K Adv Server domain name is “X.y.z”. But, when I try to establish TRUSTS from the W2K to the NT 4, I can’t because the DOMAINS names look to the NT 4 to be the same.

Can I rename the ACTIVE DIRECTOR names?

How do I get around this limitation?

Thanks for the help