As with most things in linux, there are several ways to change the ip address.
The command: redhat-config-network brings up a GUI tool. Under the Devices tab, you can Edit eth0 or whichever eth[?] you have.
You could type the command:
/sbin/ifconfig -a eth0 192.168.0.10 netmask 255.255.255.0
Note: change the numbers to suit yourself.
You could edit the /etc/sysconfig/network-scripts/ifcfg-eth0
Note: that's in Redhat 9. Maybe different for other distros.