Used ascrewdriver to bend the metal rail that the roller rolls on. The part that needed to be bent holds the end cap on. Once bent, the end cap pops off. The the old roller can be removed and the new roller instsalled. The rail then needs to be re-bent.
First removed the end cover and clip on the end of the rack slide. Used a flat head screwdriver to push in the clip and carefully pried it out. Then using the same screwdriver, pried up on the rack roller clip attached to the dish rack. Once clip was free of the rack, slid the rack roller off through the front of the slider. Slid the new rack roller into the slider and snapped the roller clip onto the dish rack in the same place the old one was. Carefully twisted the plastic end cover and clip back onto the rack slider. Job complete. The trickest part of the job is removing the rack slider end cover.