Open it
Schedule → Appointments, or select it on Schedule → Calendar.
Reschedule
Choose a new time. The customer is notified of the change automatically when notifications are on.
Cancel
Cancelling frees the slot. The customer is emailed when the appointment has an email address, and a text is sent when text messaging can reach their mobile number. Waiting customers are emailed a claim link when the business has a plan. A business with no plan yet does not send that waitlist email.
Mark what happened
Update the appointment's status so your reports and your client history stay honest — including no-shows.
Notes
Add notes to an appointment for anything worth remembering next time. Notes are internal and never shown to the customer.