You will need to rename all three scripts and change their references to the new names.
There are two places in 'wxgr3hanis.php' where 'inc-gr3hanis.php' is called. Change those two 'inc-gr3hanis.php' occurrences to your new 'inc...' name and save the modified 'wxgr3hanis.php' with a new name. In your 'inc-gr3hanis.php' change the single reference to 'wxgr3hanis-iframe.php' to your new iframe script name, and obviously change the iframe script's name as well.
In summary:
1) Change the iframe script's name by saving it unchanged as the new script while leaving the original iframe script intact;
2) Change the single reference in the includes script to the new iframe name, and save it as your new includes script with a new name, again leaving the original script intact;
3) Change the two references in 'wxgr3hanis.php' to 'inc-gr3hanis.php' to refer to you new includes script and save the new main script with a new name while leaving the original main script intact.
(BTW, when seeking help, providing links to the scripts in question is always a good idea.)