Thought anticipated

This trick needs 52 cards, which a spectator can shuffle.

Start by asking spectator 1 to choose a number between 1 and 10. Then show the first 10 cards of the deck and ask them to memorize the corresponding card. Ask spectator 2 to also choose a number, between 20 and 30.

Now, while talking to the spectators, put your hands behind your back or underneath the table and add 16 more cards to the 10 cards you showed earlier. Flip this packet, and show now on the table the other side of the deck (so that the 10 cards are on the bottom).

Tell now that you moved spectator 1's card to spectator 2's position.

Count the number of the spectator 1, deal that many cards and show that the corresponding card isn't the correct one.

Now subtract spectator 1's number to spectator 2's number. Deal that many cards on the table. When you arrive at that number, say that's your unlucky number, and while flipping the card "just to make sure", flip the deck too.

Finally, continue counting to spectator 2's card, and reveal spectator 1's selected card.