In what order is my trainer card gonna change into?

Question

Okay what if I get 50 wins at the battle maison and my trainer card turns gold. Will it change to silver or stay gold after I catch all Pokemon in kalos?

Answer 1

Your card changes color in this order:

Green -> Blue -> Silver -> Gold

The accomplishments for changing the color are:

1. Defeat the Elite Four
2. Complete Kalos Pokédex Dex
3. Battle through one of the Battle Maison facilities and defeat the leader at the 50th streak

Serebii

So to answer your question, there is no way that conversion would happen. It would just go up one color from whatever it is now.