Carol,
when you say pre-recorded, is it like a midi-file, or a sequensed song where you can see the chord-changes in the display?
If so, then the style/patterns is in the composerbanks, and the only thing you have to do is turn off the sequencer, and set the PR as you normally do when play songs with styles/patterns or whatever you like to call it.

If it is a kind of midi-format, where the song is only in the sequenser, then it's more complicated. then converting, copying, patse etc. is the only way to make it as a pattern/style or.......
GJ