If you are the account owner (or have root user permissions) you can manage your direct debit billing details right inside your Eagle account.
Log in to Eagle
In the top right corner, click 'Settings'
In the left menu, click 'Billing & Subscription'
If you can not see the Billing & Subscription page it means your user login does not have permission to access it and you'll need to contact your account owner to update your payment details.
Once on the Billing & Subscription page:
In the bottom left corner of this page there is a 'Payment Details' section
Click 'Edit', select Credit Card or Bank Account
Enter your new payment details
Click 'Update' to save