You can't convert the card when you get the card for the first time. However, whenever you get the exact same card again (same card, same stars), it will automatically convert to resources and materials.

Since the Star quantity is decided when you receive the card, it is not possible to increase the Star quantity for that specific card. When you receive a duplicated 1-Star Card, you will get the Map Pieces for 2-Star Card; when you receive a duplicated 2-Star Card, you will get the Map Pieces for 3-Star Card, and so on.

In addition, there will be extra duplicate rewards for duplicated 2-Star to 4-Star Card!

Thank you for your support! 😊