If they are Schwintek slides, I think you are supposed to remove a screw from the motor, then slide the motor down a channel which disengages the pinion from the rack.
Then you can manually push in the slide out.
Since you can not necessarily access the motor to put it back into place when you retract the slide, you need to use a 2x4 or bracket that came with the unit to prevent the slide out from extending when as you drive down the road.
Apparently, units made in some years do not come with a bracket. My rig did not come with a bracket, so Lippert recommends jamming a 2x4 into the slide out.
The only thing that works on a RV is the owner...