[X-Unix] Altering system parameters (e.g. IP addresses) on Mac OS X server

[Ken Rossman]

Folks,

I have a need to change some IP address range info on a Mac server  
platform
(running OS X server), but don't have a physical console, and can't  
remote
desktop into it.  I can only (at present) open a command line (ssh)  
shell to it.

I need to change the server's default IP address to a different  
network range,
then reboot it, and hope I can still get on it.

What are the command line incantations I need (beyond just editing / 
etc/hosts,
which I have done already) to make the server's default en0 address  
change from
one network to another.

Thanks,
K