In Cornerstone there is an option when deleting an appointment to move to the "Tickler File". This does delete from the appointment schedule, but Weave will still sends reminders as if the appointment wasn't deleted. The appointment database within Cornerstone has a field called appttype (not appttype_id), that will contain 'A', 'B' or 'T' for appointment, block or tickler. Those appointments no longer exist and owners should not be getting reminders