Hi, is there a way to change the distance between loft sketches?

I'm trying to change the dimensions of a loft. I drew shapes on planes a set distance from one of the main reference planes. When I try to change the location of the plane I'm only able to choose from existing surfaces.

Since the original plane was created using <--D--> from reference point, I would have thought I could go in and change the distance, but it doesn't show any of that info when I select 'edit sketch plane'. It only allows to me to replace the plane with the main plains for other surfaces.

I've also tried creating a new plane, but when I go back to editing the loft sketch plane it isn't visible and it won't select from the list.

Thanks!