Text reminders get ignored. A real conversation — confirm, reschedule or cancel in one call — is what actually keeps a slot filled.
A one-way text or email reminder is easy to ignore. A no-show still costs the same slot, the same staff time, and the same lost revenue.
Manually calling every appointment to confirm doesn't scale past a handful of bookings a day — someone has to sit and dial the list.
When a reschedule is needed, the caller usually can't act on it in the moment, so it turns into a missed call, a voicemail, or simply a no-show anyway.