How to check in audit action when users updating actual/planned time in shipment stop tab

We need to check weather users updating actual/planned arrival/departure time in shipment stop tab from buy shipment screen manually. As based on some conditions we need to allow/disallow update of the dates on shipment stop tab.

So, we need to understand, how to check in audit action if users are updating the dates in shipment stop from buy shipment screen then we need to put that audit action in action check to restrict user. We need to display error message on screen to the user when they will be trying to update the dates in shipment stops.