Deception Perception by Allen Ackerman.
This effect can be done with any 2 normal decks, and if you want to perform something that’ll definitely fool every person in the room, then this is the effect for you! Begin by taking 6 or 7 cards from the Blue deck and have a card selected from the Red deck. Place the Red selection among the Blue cards and then make the magic happen… Immediately the cards are spread to show everything has instantly reversed itself - all of the cards are now Red and the selection has now become the only Blue card among all the Red! Some consider this to be a more powerful rendition of Red Hot Mama, where only 1 card changes. But you’ll have to try it yourself to know for sure and you can learn everything you need to know in less than 5 minutes!
From: "Easy to Master Card Miracles #9" DVD.