Review the appointment and its calendar connection before changing who is invited or cancelling it.
Steps
Open the appointment from the calendar or the lead's appointment list.
Review its date, time, host and connected calendar, where applicable.
To invite someone, use Add Attendees to select a contact/employee or enter the intended email address.
Save the change and check the resulting appointment status.
To cancel, reopen it and use Cancel Meeting or Cancel Appointment, then review the confirmation.
Manual and connected appointments
The appointment dialog offers Enter a time manually, Choose an available time now and Send an appointment page when supported. A manually entered meeting can optionally check and sync to a selected connected calendar. Review what will be sent before saving.
A request is not a booking
Sending a scheduling page emails a link so the recipient can choose and confirm a time. Nothing is booked until confirmation. Cancelling that pending request is different from cancelling an already booked appointment.