Subject: Reminder: your appointment on {{date}} at {{time}}

Hi {{name}},

This is a reminder that you are booked for {{service}} on {{date}} at {{time}}.

Location: {{location}}
With: {{staff}}

If you need to reschedule, reply to this email or call {{phone}} at least {{notice}} before the appointment.

See you soon,
{{business}}

SMS version:
Hi {{name}}, reminder: {{service}} on {{date}} at {{time}} at {{location}}. Reply if you need to move it.