Mine has a threaded fitting on the back where the interior water line connects. Basically, once the threads loosen, the connector spins rather than loosening further, so you have to get a hand on the back and either hold it firm while you continue to unscrew the outer piece, or unscrew the fitting on the back itself while you hold the front tight.
If you can't pull it out far enough to grab the hose behind the inlet, you will have to reach up behind it. On some rigs you may have to remove a cover plate to get your hand behind there. Each one is a little different.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL