On my Roland boards, I set up a color sound that I bring in with a EV5 pedal.
This is the best way for me to change the sound..You can set it up in a way that you can actually switch from one sound to another via EV5 pedal, or blend the two together..
I can also change to a second tone with velocity switching..
If you can not do these things with a Yamaha, let the drummer[fill] cover you while you make a tone change with your right hand...Also I repeat the intro, this allows plenty of time to change tones..
As DonM has stated ,I also use the lockouts on my Roland..this allows a whole new ballgame,without striking out..