There are 2 ways:
1-From the payment screen:
When you make your next payment, go to your Account, click “Make a payment” and select “New Card” from the drop-down. You will be prompted to enter a new credit or debit card. We recommend using the debit card tied to your direct deposit account. You can also opt into auto-pay at this time.
2-At checkout on your next purchase:
If you make another purchase, you can update the card on file. All existing orders on auto-pay will be switched to the updated card on file.