If you use Stripe to pay your DPG subscription you can update your card details by going to Accounts.
Log in to Accounts
From your Dashboard, click the Manage button and log in with your username and password. Click the cog icon to manage your account then click the Payments tab.
In Payments select the Manage Payments tab and click the Update button.
Update card details
Enter your new card details and click Save card. This card will now be used for future subscription payments.