Keynote - edit presentation page size from 16:9 to A3

We have created a 20 page detailed Keynote presentation. Unfortunately we made the page size widescreen TV, when we actually need to print it on A3.
We need someone to go through the presentation and adjust the page size of each slide, and then reformat the presentation so it fits the A3 page perfectly.
This is also needs to be done super fast, by 8am tomorrow UK time (by 8am GMT Monday 28th Oct.

Here's a link to see the file:
https://drive.google.com/file/d/1VgGN0XN1DwYVSygO_uLvEpczpO_2LdC-/view?usp=sharing