Depending on the lights in your unit, use your hand and turn counter clockwise on the lens and it should come off.  I had a few that were stubborn to remove and ended up using my 15" channel lock pliers with a rag between the lens and the pliers and carefully removed them. 

Chris

Didn't say what year of RW you have. The early ones unscrewed as mentioned. The later ones were one piece that the entire fixture had to be replaced, not sure how to remove.

my rig is a 2015 gk.I have unscrewed the lens cover  but unable to see how the fixture is removed.there are no visible screws that holds the fixture.

Since you removed the lens and can't see any screws securing the light fixture in the hole, then the fixtures are held in with the 'mouse trap' type of springs. See if you can carefully pull the fixture down some by the edge until you you can see the spring holding it in place. Be careful that you don't break or crack the ceiling panel itself OR have the strong springs smash your fingers like a mouse. Some lights had the springs holding them in and sometimes they still used a few screws to keep them better secured.

Chris

On my 2015 38RL, the LED lights are held in by a strong spring clip. The three screws in the mount are just to hold it in place. You pull down on the fixture where it feels like you're going to rip/break the ceiling. I couldn't find any way to replace the LED, it's soldered in place - have to replace the entire fixture, and the replacement is much easier to install since the spring tension is less.