To make changes to your personal backup card linked to your Forma card (U.S. only), log in to your Forma account, select your name on the top right corner, select “View or edit profile”, then select “Linked accounts.”
Under “Credit or debit card” you can remove, edit or add another card as a backup payment method.
For more information on how to remove your personal card, refer to the article How do I remove my personal credit card from my Forma account?