Ask the current builder where they stopped work
The tailcone/empennage construction plans are sections 6-12 and they are available on Vans website. If the builder has not started section 10 then i believe it would be very easy to change things up. You’ll have to get the right parts of course. Take a look at section 10 and you will see the pages where there are steps for tri-gear and tail-dragger versions. Just have to figure out what has been completed. The big things are the tail spring mount and that last bulkhead. If that part has already been done then you have some work to undo. Not sure how much disassembly that would involve.
Carrollton, GA 5GA2
RV-14 - First flight 4/7/2019. Phase I complete as of 9/11/2019!!