To update your existing credit card information, or add a new credit card, for specific subscriptions from within your Untappd for Business account, you can do so from the Billing & Invoices screen.
Click the down arrow next to your name in the upper right hand corner and select Billing & Invoices from the dropdown menu:
Choose the location you would like to update credit card info for, then click the right arrow to access the Billing & Invoices home screen:
Click View on the subscription you'd like to update a payment method for:
Click the Pencil Icon next to Payment Method:
Choose to update the payment method of all subscriptions or just the selected subscription, then click Continue:
Select your new payment method, then click Update: