Using StylePicker i selected a style and then loaded the SongDemo for that selected style.

The Style/SongDemo has the Bass, Piano, Drums, Guitar, Strings, Melody, and Soloist tracks.

However, I want to delete the Strings, Melody, and Soloist tracks. Is there a way to do that ?

In the menu under the instrument you want to delete, choose Select RealTracks > Choose No RealTracks for this track.

Or just mute the track.

Another way is to select "import an instrument from another style" then select a blank instrument from one of the four blank styles.