Scheduling and managing events using Outlook.com calendar
For Outlook on the web or Outlook.com, delaying a calendar event send is not supported in the provided documentation.
The available delayed send feature in Outlook on the web applies to email messages: while composing a message, select the dropdown next to Send and choose Schedule send. Scheduled messages stay in the Draft folder until the delivery time.
For calendar-related delay behavior in the provided documentation, Microsoft Graph supports postponing an event reminder by using the event: snoozeReminder API, which changes the reminder time for an existing event. That is different from delaying when a new or updated calendar event invitation is sent.
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