Drip in grey water drain pipe

[Golfnbike13]

I've discovered a drip in the elbow joint going into the valve of the grey water drain. What's easiest way to fix? Or do I have to cut out the pvc pipe elbow and replace it?

[Ford Idaho]

From what I see I would first remove the 8 screws that hold the valve and remove the valve I would then try to remove the elbow by twisting it while holding the pipe.

It just be loose enough to remove then clean the joints so they can be glued.