Automation: Show error if info is missing when changing the status

Automation: Show error if info is missing when changing the status

Hi, I would like to set up an automation workflow rule for sales orders so that the status can only be changed to "Cancelled" if the user first filled out the Cancellation Date. If they forgot to fill out Cancellation Date, then the status change should not be saved and the user should get some kind of error message about it. How do I do that?