You can find a list of all the constituents that have credit cards saved on file in the Saved Cards page in the Organization's setting. Open the menu under your organization's name and click on Saved Cards.

On the Saved Cards grid you will find the name, email, last four digits of the credit card as well as the expiration date info. There are also columns for the expiration month and year. You can filter the grid using the filter icon to identify cards that have expired or soon will expire. This information can also be exported via the Actions menu. 

Within the constituent's record, there are links in the Payment Info tab to send requests for updating a credit card. Note that credit cards can not be edited due to their encryption. DonorView does offer a Card Updater service to keep credit cards on file up to date. You can reach out to support@donorview.com for more information about this service.