Called by option ORB PURG RECIP - purge existing notifs: recipient/DUZ
User whose alerts you want to delete
called by option ORB PURG PATIENT - purge existing notifs: patient
DFN of patient whose alerts you want to delete
called by option ORB PURG NOTIF - purge existing notifs: notification
IEN of Notification [#100.9] all instances of which will be deleted
