How can you access cPanel like, say, http://domainname.com/xyz ? This is for security purposes.
This can be done but not recommended as it would not be of much effect security-wise.
Even if you change it, cPanel/WHM would still run on the standard ports (2082/2083 & 2086/2087) which is known to everyone. If you have a valid cPanel license then you can contact their support and get the ports changed. This coupled with a strong password (change regularly) should be good enough.
However, coming back to the original question, you can achieve it in the following way :
Go to /usr/local/apache/conf/httpd.conf
Find the following line :
ScriptAliasMatch ^/?cpanel/?$ /usr/local/cpanel/cgi-sys/redirect.cgi
Comment it out by adding a ‘#’ at the beginning and add the following line below that line :
ScriptAliasMatch ^/?xyz/?$ /usr/local/cpanel/cgi-sys/redirect.cgi