This task is very simple and can be done in two steps: 1.)  Login as root and change your server hostname:

1

hostname newhos.name.tld

Note: Don’t forget to create an A entry for your new hostname, otherwise you will get a popup message during WHM login.

2.)  Issue /usr/local/cpanel/cpkeyclt to update your Cpanel License Key, otherwise you will get Invalid License when you login to WHM/Cpanel interface.