To accept a meeting we usually create an AcceptItem.

However, in Outlook you also have the option to accept the meeting invitiation without sending a reply.
Could somebody explain what exactly happens behind the scenes (read: what i would have to implement) ?

Obviously the appointment is created in my calendar, would that be a createItem call with the details of the original appointment from the meeting message? But how is that deleted when the organizer cancels the meeting?

Whether a reply is sent or not is controlled via the MessageDisposition with you use with EWS when you accept the appointment. So the simplest solution should be just to use save eg

      <m:CreateItem MessageDisposition="SaveOnly">
        <m:Items>
          <t:AcceptItem>
            <t:ReferenceItemId Id="AAM..." />
          </t:AcceptItem>
        </m:Items>
      </m:CreateItem>

>> But how is that deleted when the organizer cancels the meeting?

There is no direct link when the Organizer deletes an appointment and doesn't send a cancelation only the appointment in the Organizer mailbox is deleted. All the changes to the attendees Mailbox calendars are driven through the Calendar Invites/Cancelations (and attendee acceptance of these).

Cheers
Glen

Whether a reply is sent or not is controlled via the MessageDisposition with you use with EWS when you accept the appointment. So the simplest solution should be just to use save eg

      <m:CreateItem MessageDisposition="SaveOnly">
        <m:Items>
          <t:AcceptItem>
            <t:ReferenceItemId Id="AAM..." />
          </t:AcceptItem>
        </m:Items>
      </m:CreateItem>

>> But how is that deleted when the organizer cancels the meeting?

There is no direct link when the Organizer deletes an appointment and doesn't send a cancelation only the appointment in the Organizer mailbox is deleted. All the changes to the attendees Mailbox calendars are driven through the Calendar Invites/Cancelations (and attendee acceptance of these).

Cheers
Glen

• Marked as answer by Simon Hain 16 hours 54 minutes ago

Thanks, i wonder why my that did not work when my colleague researched it.

As the message gets saved in the draft folder we'll have to use a deleteItem as a follow up i guess.