my opinion is once your a Pro you should not go back to amateur.....
the current written rule is that only a Pro that is not eligible for a masters class can go back to being an amateur however NABBA HQ is re-writting this i believe and a Pro no matter the federation has to serve a 2yr ban from competing back in the Mr classes ........(James did this and so did Mike King)
However the old NABBA Pros did not carry their status into the new Pro league with NABBA (everyone had to requalify) they did back date the card for 3yrs when it was brought in to include the class winners from the NABBA Worlds and Universe for the previous 3yrs (i think this was the class winners from 2011) so anyone who held the rank of Pro before 2011 would have it stripped and would need to re-qualify as a Pro to compete as one.