How to change the IP and name of the server in rhn web site?

Hello,

We have recently moved our server to another building. The domain name has changed, and the server does not have a visible IP from outside the local network.
How can I change the server name, and the IP on the redhat network website so that the server will be recognized and I might keep up to date my system ? The IP of the server is a local adress such as 192.168.xxx.xxx ... Should I give the IP of the institute gateway ?

Thank you in advance
Pierre.