My customer assigned a registration code to the wrong user. How can they change the access and send the code to someone else?

When a registration code is associated with a user that information will display at the bottom of the registration page in the Registrations section.

To remove access click the Remove link for that displays next to that user.
The Registration code will be moved to the Order Registration Codes section of the page and available for reassignment to another user.

The originally assigned user will no longer have access to the product or any completion information.