Talk:Tutorial Guide/@comment-88.160.182.3-20150429150844/@comment-25523655-20150429152357

When you receive a duplicate copy of a card that you already have, the duplicate copy will automatically be merged with your original copy, raising its max level (this can be done four times at most).

You have the option of selling cards in exchange for Produce Points. Tap on ポイント交換 (second button on the right column) on your card screen, select the cards you want to sell, and click on 確認 (red button).