Assigning a MIDI patch to a track that contains a RealTrack won't do anything, as there are no MIDI notes there to play. The RealTrack would be unaffected.

The easiest solution would be to use the RealTracks Picker to pick another bass RealTrack, but if you really want to switch to MIDI, there are a couple options.

You can right-click on the track name and go to "Select custom MIDI style for this track", which allows you to pull any track from any MIDI style, but you'll need to know which MIDI style has a bassline you like.

I'd right-click on the track name and hit "Select MIDI SuperTrack for this track", which will generate a MIDI SuperTrack. That method is far easier.

Thanks
Kent
PG Music