An instance cannot change stages without some interaction. You can send notifications after fixed periods of time. After 3 days send a notification to the next person in the workflow. When they open the form if your specific conditions have been met check the approved box.
We have people opening the form without user accounts (via email) so we can’t add arguments based on the user. Is there a way to code a behavior condition in the stage that after 3 days it moves it to the next stage then notifys that person? Does the form check conditions of each stage daily/hourly or some time or does it sit there after the notifications waiting for a response?