Cannot switch a track back to MS Basic after selecting another instrument option

I had a sound in the mixer marked as using MS Basic. I then thought I'd try a sound in Muse Sounds to see if it was better. After I selected the sound, the MS Basic option on the menu is replaced by the Muse Sounds instrument and there does not appear to be a simple way to switch back to MS Basic for that one track. The same is true if you choose an instrument through VST or soundfonts from the menu, Does anyone know how to switch it back to MS Basic? The partial workaround is to reset the sound selection in Playback Setup but that messes with other tracks in the piece.