Has a change occurred?

I allow editing on an Access form only when the user has specifically asked for it by clicking a button which sets AllowEdits=True. When she has finished editing she reverts to read-only mode and the update is effected by AllowEdits=False. I want toask her whether she actually wants the changes, and, if she does not, invoke DoMenuItem…acUndo, but if she has in the edit mode changed nothing there arises an error message. I would shield her from this. The obvious shield is a test whether therehas been any change, or whether an update is pending. How can I make such a test?