If you create an appointment and change the owner this doesn't mean that it would be appear in the new owner's calendar.

Appointments only sync to the calendars of the Outlook accounts which are part of the invitation. If the new owner is not included in the invitation, the appointment will not show up in his calendar.

Appointments will not be synced automatically to the new owner's account, since the invitation itself was created by first owner.

We need to have this server-side synchronization functionality since we want the created appointments in CRM on behalf of other users to get synchronized in their Outlook calendars without sending invites.