Based on how you open the Appointment Info panel–either by selecting New Appointment or Modify Appointment in the Appointment Book's context menu–do one of the following:
If you are creating a new appointment for an existing guest (by selecting New Appointment):
In the Appointment Info panel, start typing the guest's name, phone, or code, and select a match from the list of suggestions. Then, click History at the bottom of the panel.
If you are modifying a guest's existing appointment (by selecting Modify Appointment):
The guest's information automatically appears in the Appointment Info panel. Simply, click History.
The Guest Details page opens in a new window with all the information about the specified guest.