You can update your FFL listing under My GunBroker>Account Information. From the Account Information page, scroll down to FFL Information and click Edit.
Once you update the information, GunBroker.com manually reviews it before updating the information on the site. You cannot make any further changes until the updates are reviewed and posted to the site.
You cannot change your FFL license number. If you need to change your FFL license number, please contact support for assistance.