You just need to make the necessary DNS changes and point the new domain to your DA Server's IP.
Then in the server, you may want to change the hostname - you do this via command line/console (SSH). you will find the hostname in /etc/hostname
Then in DA go to: http://<yourserver>:2222/CMD_ADMIN_SETTINGS and make the necessary changes in there.
I don't think so.Will this automatically rewrite everyone's zone file to reflect the new nameservers?