I will explain that there are four cards. The cards are four Queens. I will cover the four cards with a handkerchief and say that I will make the Queen of the suit the audience freely chooses disappear. Let's say the audience says "Hearts." The magician takes out the cards one by one from under the handkerchief and shows them. The first card is "Clubs." The second card is "Diamonds." The third card is "Spades." And the fourth card... is a blank card, and only the Hearts, which the audience specified, have disappeared.