You can change Lockbox code by going to the Listing address > Edit Showing Settings > Lockbox & Showing Instructions > Lockbox Option > Regardless of whichever option you choose to select, always make sure that you type in the Showing Instructions Comment Box the instructions on how to view the property.

NOTE: For every changes made, please click SAVE & UPDATE which is found on the bottom part of the page just to make sure changes will be applied.