Backfire by R. Paul Wilson

Here’s what happens:
The magician has their audience members hold a cloth at the corners like a small stage. Then the magician extracts the kings and the aces from a deck of cards, and openly places the aces face down on the cloth. One at a time, and with no visible moves, the kings and the aces change places. Once all four aces and kings have transposed, they instantly switch back. Then the magician can hand out the cards for examination.