The style creator is not very intimidating to do something simple like an instrument change. It seems like the simplest way, why not try it. Just pick out the track with the guitar arpeggio, change instrument to piano or whatever, save the style with a new name, like piano serenade, then try it. If you don’t like it, then maybe you can take the next step and re-record just that one track yourself. Save it, see how it sounds. It’s all trial and error. You can’t do any harm.
Mike