You need to edit the following files:
/etc/sysconfig/network-scripts/ifcfg-eth0
or /etc/sysconfig/network-scripts/ifcfg-venet0
/etc/sysconfig/network
/etc/hosts
change the IP under the localhost:
127.0.0.1 localhost.localdomain localhost
YourIP hostname.domain.com
/etc/sysconfig/network
change hostname = hostname.domain.com
You will also need to change it on your VPS control Panel
After all your changes you need to restart Apache: service httpd restart
.