Here is the way to change or modification ip address through command line. Do all the command in root privileged.
To set a static ip
#ip addr add 192.168.xxx.xxx dev eth0
to delete a static ip
#ip addr del 192.168.xxx.xxx dev eth0
to set dynamic ip
#dhclient eth0
to set route for static ip
#route add default gw xxx.xxx.xxx.xxx
to clear all ip setting
#ip addr flush dev eth0