Expression pedal Box with 2 100k pots and a TRS jack using relay switching

[sidewinder]

Hello, I'd like to build an expression pedal box with that will allow me to switch between 2 100k pots using the same type of switching system that allows one to change channels on an amplifier. The pots would then output to a TRS jack which I would connect to my delay pedal, allowing for 2 different settings. Could anyone explain to me how to do this?

Thank you!