If the buyer wants to keep it; needs to buy a new SKIM module and have it programmed to the new PCM by a competent programmer. Once a SKIM module is programmed to a certain PCM it cannot by undone. Like cutting a key.
If the buyer does not want to keep it; unplug the SKIM module at the steering column ***BEFORE*** the new PCM is plugged in. Else you’ll brick the PCM and it will need flashed.