Reply to Jumping from 4FX to 2FX in TP2

Can't seem to find an answer in any of the threads. Anyone know how to map a button or knob to activate 4FX units to 2FX units or vice versa without going into the preferences. Basically, I want to go back to 2FX units after i'm done messing with the midi fighter without going into the settings menu. Any help would be greatly appreciated and sorry if there is already a thread with info on this.