Changing Carriers with iPhone Upgrade Program

I was wondering if anyone else came across this.

I will be changing carriers when my upgrade cycle hits in a month or two. From the 'Apple Store App' it looks like the iPhone Upgrade Program only supports upgrades being made on the same carrier.

Is there an option to participate in the program if you are switching carriers and want to pull your existing number? I'm hoping that can still be done by going into the stores and just the app is limited.