Trigger for Cancel button

Summary

We're looking for a trigger that we can use to mirror the Cancel button in Oracle Sales Cloud.

Content

We want to mirror the Cancel button functionality. Upon searching, we found this link and says that "When a user hits the cancel button you'll notice the Before Rollback in Database followed quickly by the After Rollback in Database". We tried using the Before Rollback in Database trigger but the error message shows after the record is canceled(close the Summary/Details page). But our requirement is to throw an error message, once they click the cancel button and they won't be able to close the Summary/Details page without updating the required fields. What trigger/method name could be used for this requirement?