Be careful !!
Let your RV sit for at least 45 minutes, to relieve the pressure so it won't spray gasoline as you're removing it.
The filter looks like this.
The special tool looks like this. Part # K-D 3321 at your local auto parts store.
Some filter set-ups have a safety clip that must be removed first. Pinch the front portion of the clip (
as shown) to unlock the clip's "jaws". Push the clip back towards the filter and then spread it out to free it from the coupling. Take it off the line or move it forward out of the way.
Insert your disconnect tool into the coupling. Once inserted, push the tool away from the filter until the coupling releases. Use your other hand to pull the line free from the filter. Have a rag handy to catch the excess fuel that will run from the fuel line and filter.