So I bought a used Boss rc-20xl but am having a small problem. I want to do a verse-chorus-verse situation where I do all the looping live, but I don't know how to switch to an empty phrase without bending down and changing it manually. I even bought the boss fs-6 to give myself the ability to do that and I can't figure it out.

Is there a way to use a foot pedal and switch to an empty loop on a boss rc-20xl?

I had one for awhile, great looper (til mine burned out). I never bothered trying anything like that but I'm pretty sure thats what the external switch is suppose to control. You can probably google a pdf of the manual and it should have a section covering that. Thats probably where I read it from. Its been awhile though so I cant really help you beyond pointing that way.
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The Jamman has no problem switching loops with the ext f/s. But I'm not sure how switching to an empty loop will work. I'm guessing you need it to start recording the instant the previous loop ends. Don't know if it will do that.