In appointment, we see that there could be two different kinds of appointment proposed.

In one case, a physician note for "followup in three weeks" could be treated as a proposed appointment.

In another case, an appointment is already scheduled for a patient, but they want to come in sooner if possible.

This would be another kind of "proposal" rather than the as yet unscheduled appointment.

The latter would seem to want a different kind of code rather than "proposed", as it is not "pending". Perhaps "waitlisted" to indicate that this is an appointment for a patient that is hoping for something sooner. Such an appointment might reference the already scheduled appointment, but this can readily be handled as extension.

However, waitlist really seems like it effects the status of the appointment.