To reprogram a single HomeLink® button that has been previously trained, without erasing all the channels, proceed as follows. Be sure to determine whether the new device you want to program the HomeLink® button to has a rolling code, or non-rolling code.
Place the ignition in the ON/RUN position, without starting the engine.
Push and hold the desired HomeLink® button until the HomeLink® indicator light begins to flash after 20 seconds. Do not release the button.
Without releasing the button, proceed with Step 2 in “Programming HomeLink® To A Garage Door Opener” and follow all remaining steps.