If you haven’t confirmed the visit yet, to propose a different date, just select the SCHEDULE TOUR option in the communication panel – either in the top right corner of the chat window or in the side panel.
You will be able to propose up to 3 dates of the viewing in any of your venues.
If you have already confirmed a previously proposed date, click on the option CANCEL visible in the message in the chat window, and then propose a new date according to the instructions above.