When someone replies by default the following will happen.
Be default you will receive an email with the details of the reply. To edit where the replies go to go to Calendar > Edit Calendars > Edit and edit the box that says "Where should replies be sent to". You can also have replies sent to your mobile or ignore all replies. You can send the replies to multiple emails by using a comma between each email address. Each calendar
We will update the subject in Google Calendar adding either
[CONFIRMED] = Client confirmed the appointment by replying Yes, Y, 1 or C
[NOT GOING TO MAKE IT] = Client cancelled the appointment by replying No, N, 9
[RESCHEDULE] = Client replied with R
[SMSREPLY] = Client replies but we couldn't determine response type.
You can edit the language of these default text by going to Settings >Default Reminder Settings.
We will add the full details to the body of the appointment.
We can also change the color of the appointment in Google Calendar depending on the response type. You can enable coloring changing by going to Calendar > Edit Calendars > Edit and update the settings.
Please note: This article relates to Google Calendar. If you are using a different calendar this article might not be applicable.