1.Get a pack of cards and let the audience shuffle it.
2.You say that you are going to lift up one card from anywhere in the pack and i will show you that card. So what you do instead of picking up one card you pick up two cards instead and make them stick out of the deck
3.Show them the card which is showing and tell them to remember it. Then turn it round so the other card is facing you. When you are showing the card push down the card behind it (the card they saw) and split the deck were the card is.
4. Remember the pack that has there card on top and put it on top of the other pack.
5. Now pick up the card which was sticking out and rub it against the top card. Then voila the cards have changed