Mrs Smith had been given permission by Dr Darwin to take a leave of absence between her visits to the clinical oncology department. Her leave of absence had been actioned in the system and Mrs Smith was due to go home to Malton. However Dr Darwin observed that her condition had worsened, and that her leave of absence should be cancelled. Mrs Cortana the receptionist, cancelled the leave of absence in the PAS system triggering an A52 HL7 message.