Debian Squeeze Apache2 WordPress MultiSite Help.

I have a wordpress multisite installation on a debian squeeze server. I can't give you access to this machine. I tried to change the main wordpress multisite to a new subdomain and am having trouble getting it to show up. I need someone to help walk me through the changes that need to be done to make this function on the site. I will do all changes and testing, and I will tell you contents of the files you need to review.