You may play only 1 Supporter card during your turn (before your attack).
Look at your opponent's hand and choose 1 card there. Then, show your opponent your hand and have him or her choose 1 card there. Ask your opponent if you may switch those cards.If your opponent accepts, switch those cards.If your opponent declines, draw 2 cards. (You can't play this card if you have no cards in your hand other than this card or if your opponent has no cards in his or her hand.)