I also changed the IP of my VPS lately, and few things you need to look into:
/etc/sysconfig/network-scripts/ifcfg-eth0
/etc/hosts
/usr/local/apache/conf/sharedip.conf
/usr/local/cwpsrv/conf.d/cwp-ssl.conf
And, you might also need to regenerate the self-signed SSL, rebuild the vhost, and rebuild your web server & mail services. Hope this help.