Moving exchange from DC to member server

Back when exchange 2000 came out Microsoft recommended to install exchange on the domain controller and we did, but later they recommended to install it on a member server, so it was I need to do.
I have exchange 2000 server running on a 2000 server domain controller and it is the first server in the forest of AD. I have 2 other domain controller in the forest. How do I demote the exchange server to a member server and make one the other domain controllers the master domain controller and willthis effect the mail coming into the exchange server.