To remove your card details from your account, go to "My account" and click "remove" next to your saved card.
You'll see a confirmation popup.
If you'd like to change the payment method for your account, you'll need to wait for the next time you make a pledge to a project. When you enter your payment method there, you'll just need to click the "save the card" button.
NOTE: Your card information is safely and securely stored by Adyen. Gamefound doesn't store your payment information apart from the type and last four digits of your card number.