Yes. If a customer designates their computer as a trusted computer that can use saved cards (using the Trust This Computer button on the order confirmation page in checkout), they can change their trusted computer settings from their My Account page.
In order for a customer to change their trusted computer settings, they must sign into their My Account page using the computer they wish to change the trusted computer setting for. Once signed in, a customer must click the Saved Cards tab. On the Saved Cards page, the customer will see the following message:
"You've previously indicated that this is a trusted computer. Click on "Do Not Trust Computer" if you no longer wish for saved card information to be available to this computer during checkout from this store."
To change their computer settings from trusted to not trusted, the customer must click the Do Not Trust Computer button.