How do you unlearn sears garage door remote 139.18191?

According to Sears / re:139.53681B (gray case & blue buttons): Climb up on a ladder, to the door opening unit and remove the cover. Find the "smart" button (it's the only one you can push). Push the smart button and the light will illuminate for 60 - 90 seconds. Descend the ladder within the "illumination window" timeframe. Aim the remote at the unit and push the large button once; the light will flash. If programming two remotes, push the second remote's button immediately after the first. Re-ascend the ladder and replace the cover.