Jill, It can be done on the board's internal sequencer, but it's a bit of a chore. There are instructions which are much better than I can describe it myself at joe Water's excellent PSR2000 site. The actual page that describes how to change voices in a midfile ( song ) is : http://psrtutorial.com/Lessons/L_Personalizing/LP_SongsAdj/LPS_Voice/lps_voice.html

You might find it much simpler to do voice edits in an external sequencer that allows instrument definition support for the PSR2100 such as Sonar, Cakewalk Home studio, Cubase.. etc. I have Sonar and all I need to do is to open the midi file inside of it, insert a program change(s) based on the PSR2000 patch list, and save and I'm done. Of course this can be done in any sequencer that allows patch number and bank selections to be inserted, but without a patch list, the proper patch / bank numbers have to be inserted manually. I think that's still easiier than trying to do it in the board's internal sequencer.

AJ