Miracle Card Boxes

You show 2wooden  boxes content of 2 bicycle deck red and blue deck. Ask spectator choose one eg Red deck. The box content blue deck is closed and keep aside. Take the red deck from the box. Shuffle it to show every card is different and back is all Red. Ask spectator to choose one card . Show the card eg. Ace of heart. Magically the selected card  becomes blank card.  Then ask spectator to open the other box content the blue deck, when it open the blue deck is gone, and only a folder red card there. When unfolded it's the Ace of Heart. So the question now where is the blue deck . As climax the red deck now spread out and change to Blue Deck.