You can convert audio to midi in a way, yes. With drum tracks.
Say for instance that you have a kick track you don't like the sound of... start by bringing the track view up, and move the kick track to the very top row, you'll understand why later on. Highlight the track and go to process > audio > extract timing Mess with the parameters until you get an X on every initial kick transient and not in places where something bled through or on the 2nd part of the kick transient. Save it when its right, and open a midi track. Paste your new midi file in the new midi track, and set up whatever you use for drum triggering (dr-008, Battery, whatever) and pow. Perfect. It works quite well, and its great for replacing a crap kit with crappy old heads on it. This feature combined with DR-008 and Drumkit From Hell is fast, easy, mostly flawless, works great and when properly used, invisible. I use it all the time to replace kicks and to add a little snap to the snare track. If you dont overdo it, the results can be incredible.
I have a song up that I used this exact same method on if you want to hear it.