Renaming Fields (update to #690)

[mghenderson]

I've been banging my head against this wall for a while, reaching out to see if someone else has a better perspective/approach. I have a pdf with one page that I'd like to turn into many, changing the field names to be unique. Basically I'd like some help applying/updating the solution from #690, as I haven't been able to proof-of-concept their solution. Any help/direction would be absolutely helpful, even if it points me away from this solution.