Unfortunately there is no way to simply update a credit card in the HONK system.
HONK uses a secure payment processor and therefore we do not store any payment information, which is great for security, but does not allow you to update your payment info.
If you have a new card, even if you just want to update the expiry and CVV you must add it as a new payment option.
We recommend putting the nickname 'new' if you are adding a new card with the same last four digits as your old card to avoid confusion.