On the MR8 none HD there is little as when you record over a track it writes it to that file. (there is a setting that effects this, has to do with how much undo you have) On the HD models each recording is a new file, so to get the final track off you need to use Wavmanager, so it will piece in the rerecorded parts, also using Wavmanager it will add slience to the start of a track that starts part way through so they will line up when opening in something else, so you are not trying to find the spot with just a short file.
example: I record a guitar track on 4 but I fulb a small part 75 seconds in and a record over that short part, then a vocal on 3, I have drummer record on to 1 and 2. The vocal and drums don't start until after a 30 second intro from the guitar, so I started there recording at 25.
If I just copied the files over I would have 5 files.
The guitar with the flub
the guitar fix
the vocals
drum 1
drum 2
The guitar file would be 25 seconds longer then the vocal and drum tracks and I would have this short 15 second file thats the fixed guitar part.
With wavmanager I would have 4 files all the same length. ( they my be a bit short as it doesn't add to the end of tracks) So when I opened them in my software they would all line up on the zero mark and the flub would be fixed.
Do remember that with the CF units you can use a cardreader to move the files around, there is nothing special about the MR8 when it comes to this. The data is all on the card.
Hope this helps.