To change Default Ip address for Namebased Sites :
edit /etc/virtualhosting/namebased_ip_addrs
edit /etc/hosts
edit /etc/httpd/conf/httpd.conf
edit /var/www/html/MyAdmin/wp.config.inc.php
edit /etc/detectchanges/IP
then run
#/usr/local/bin/NBDetectchanges
Resave all the named-based sites.