Can I make a Domain controller into a server on another domains
I have a client with a server which is on it's own domain (called backup domain). It was intended to be a backup server (I'm not sure why it was put onto a different domain) but we can't create a trust between this Win 2008 server and the SBS 2003 server on the other domain. So I've given up trying that route and am thinking of making this server a backup server on the main domain.
Currently the server in question is the Domain controller for the backup domain - so my question is, can I change it to be an ordinary server on the other domain. At the moment the option to Change the domain (or name, workgroup) is greyed out so I can't just try it and see what happens. Does anyone know if this is possible and if so can you point me towards a process for it. (Or should I just format it and reinstall and add to the main domain?)