Not sure what it would entail for an ATP, but I know for my guy, he had the letter from the FSDO cc'd to me so I could check it out and plan on what we needed to work on. Without the letter sitting in front of me, I know it's not a whole checkride over again. It's basically a list of items that must be completed with a DPE and shown satisfactory and then the FAA will issue you your pilots certificate back. From what I can remember here are some of the items that you will have to demonstrate to the examiner:
Basic control and operation of the aircraft from taxi out to taxi in
Being able to find a suitable place of landing in the event of engine failure
Being able to spot other aircraft in the air (at night seeing the nav's to determine direction of flight)
Being able to look down at charts for pilotage, frequencys, you name it while in flight
That's all I can remember right off the top of my head..the only problem my student seems to be having is like I mentioned before is the flare. But other than that, he said he can't really tell the difference.
So to answer your question, I would immagine it would be the same regardless. Not 100% sure, but I'm pretty sure.