Generally morphs like this are either a FBM or PBM which is Full body morph or Partial Body Morph. A PBM would split the morphs into usually a head and body morph.

I suspect this one is a FBM which isnt as easy as you would think to dial back to Genesis feet there are some processes using Z brush that work detailed here :http://www.daz3d.com/forums/viewreply/82975/. THis works by combining the parts of the morph you want while leaving the rest of Genesis at default.

But unfortunately there's no easy fix, its generally best done at the creator level. And is something to look out for when you buy a product.