Once you add credits using a credit card to your CallHub account, it gets saved in your account for future use. In order to change/update card details, you just need to use your new card and add credits once. This will replace the previous card details with the new one. You may refer following steps for details.
Step 1: From dashboard, click the $ sign after logging into your account.
Step 2: Select amount that you wish to add and click "Add credits" button.
Step 3: Click on "Pencil" icon to change card.
Step 4: Enter New Credit Card detail and click "Pay Now" to make the payment.
After the payment is made, old card details will be overridden with new.