After you click one of the buttons to respond to a meeting request, you are given three options for your response:
Include a message with your response Do you need to let the meeting organizer know that you might be late? Maybe you need to verify if lunch will be provided at a lunchtime meeting or whether you need to bring anything to a client presentation. When you respond to a meeting request, you can send a personal note to the organizer.
Only the meeting organizer will see your message — it doesn't go to the rest of the attendees.
Send the response right away The meeting response is sent back to the organizer's Inbox and the meeting entry is updated in the Calendar.
Do not send a response at all The meeting is added to your Calendar, but the meeting organizer won't know your plans.
Tip It's always best to send a response to a meeting request.