Why do you expect the change to show in the AppointmeentItem if you never modified it?
Have you tried to open the corresponding appointment using MeetingItem.GetAssociatedAppointment and modify it as well?
Question
I updated meeting item in Application_ItemSend event handler, the "sent" message shows the change; however on my calendar, the change doesn't show up. What's wrong?
Solution
Why do you expect the change to show in the AppointmeentItem if you never modified it?
Have you tried to open the corresponding appointment using MeetingItem.GetAssociatedAppointment and modify it as well?