Yu-Gi-Oh! The Eternal Duelist Soul Cheats

To Duplicate a card, First you must have another person you want to trade with. Then you both must select a card. The person who is getting the card must pick a card he/she doesn't want anymore. Then the person who has the card wanted must click "Trade it now," the person who is getting the card, waits till the other person gets their card back. Then the person who's getting the card must click "trade it now." You will notice that you now have the card you wanted, and the person you are trading with has their copy as well.