Should be able to "undo confirmed" and "undo arrived" on/from calendar view.
Current workaround is to go into front desk mode and manually slide these appts back to the intended state. Example of this would be client comes in, front desk checks a client in but it was the wrong client. Service provider was notified, and gets ready only to find it was an error. Adding procedures to go into front desk view and correct the state is tedious and quite forgettable unless staff is vigilant or errs on the side of being perfectionists. Placing this on the calendar view's UI simplifies salon logistics by being intuitive. Marking something as unconfirmed would allow for salons to have a little more control over marking clients correctly regarding if further confirmation is needed for the upcoming appointment.