Why can't I just change the expiration date of the credit card on file?

Our system is not designed to be able to simply update the expiration date for the credit card you have on file with us. The system requires that the entire number be re-entered. To change your credit card on file, log in to your account at www.parkmobile.com with your username and password. Click Payment Method on the left navigation menu, then Manage Credit Cards, and then Edit Card. After adding the new card details to your primary credit card, click "Save".