It's certainly possible if you start with a multi-track project -- each instrument on its own track. Then you can change the balance and placement of each instrument as you want. Then export a new mixed show with the changes in it.
You can't separate instruments once you make a mix.
There is one tool called Vocal Removal that can, in some cases, remove the lead singer from an orchestral mix, but that's it, and it fails on more songs than it succeeds.
There is one more way to do this. If you have a MIDI mix, you can export that into a music track and make a new track with a different mix any time by changing the MIDI construction.
I know it's possible.
How do you know that?