Question:  With the appointments scheduler, when adding a new patient (i.e. a patient without a patient number who hasn't had an appointment) to the scheduler by selecting a time slot and entering the last name in the name field... if an existing patient with the same last name exists, the appointment will be created for the existing patient rather than the new patient.

Answer:  Click on the time slot.
In the LastName field (up top) enter the LastName, FirstName
(all in the LastName field).
Click on the "Save" icon.