By default, single property websites will display the License Number of the Listing Agent. However, in the event you are an Agent advertising a listing with the Listing Agent's permission and would like to change the displayed License Number you may do so by following these steps:
Click on View Facebook Ad.
Click on "Learn More" in ad editor.
Scroll to bottom of listing page.
Click on license number and enter your own.
Close tab and go back to ad editor to continue with purchase.