adding new Domain Controller (from NT –> 2003 server standard)

Hello all and thanks in advance for any help.

We currently have 3 servers; NT server (current DC), NT server (BDC), and a 2003 server (application server). We just got a new 2003 server and will make this our new DC. I am going to leave the old NT server running (on different domain) for some legacy hardware.

My question is this: Can I move the NT domain controller to a new domain and just move the new 2003 DC to the old domain? I currently have the new 2003 server up and running on the new domain that we created, so can I just “swap” domains with the old NT server?

Or should I demote the NT domain controller and then add the new 2003 server to the original domain, eliminating the second domain?

Thanks again.