How to Manage Event Responses

Update existing events, decline invitations, cancel meetings you organised, or delete events from your calendar — all via the manage-event tool.

Update an Event#

“Move the 2pm meeting to 3pm and add Sarah”

tool: manage-event
params:
  action: "update"
  eventId: "AAMkAGR..."
  start: "2026-05-27T15:00:00"
  end: "2026-05-27T16:00:00"
  attendees: ["alex@example.com", "sarah@example.com"]

Update changes only the fields you pass; everything else stays as it was. Available fields: subject, start, end, attendees (full replacement list), body, location, isOnlineMeeting, sensitivity, showAs, importance, categories, reminderMinutesBeforeStart. Use dryRun: true to preview without applying.

When you change attendees, everyone already on the event keeps their attendee type: an optional attendee stays optional and a booked room stays a resource. Anyone new is added as a required attendee. To set or change a type, pass an object instead of an address — an explicit type always wins:

tool: manage-event
params:
  action: "update"
  eventId: "AAMkAGR..."
  attendees:
    - "alex@example.com"
    - { email: "sarah@example.com", type: "optional" }
    - { email: "boardroom@example.com", type: "resource" }

If any attendee is given without a type, the event’s current attendee list is read first, so the dryRun: true preview shows the types that would be sent.

If the server has a recipient allowlist (OUTLOOK_ALLOWED_RECIPIENTS), every address on the new attendees list, rooms included, must be on it. One blocked address refuses the whole update (Event update refused: …): nothing changes and nobody is emailed, and a dryRun reports the same refusal. The allowlist isn’t checked when you change other fields without passing attendees, or on decline, cancel and delete. See Send Email Safely.

Updates preserve attendee RSVP state — unlike delete-and-recreate, attendees keep their accepted/tentative status on the rescheduled event. Attendees are notified of the change.

Decline an Event#

“Decline the 2pm meeting — I have a conflict”

tool: manage-event
params:
  action: "decline"
  eventId: "AAMkAGR..."
  comment: "Sorry, I have a conflicting meeting at that time."

A decline response is sent to the organiser with your comment. Leave out comment and the response goes without a message — nothing is added on your behalf.

To decline without telling the organiser (for example, an invitation from a mailing list), pass sendResponse: false:

tool: manage-event
params:
  action: "decline"
  eventId: "AAMkAGR..."
  sendResponse: false

Cancel an Event You Organised#

“Cancel tomorrow’s team standup”

tool: manage-event
params:
  action: "cancel"
  eventId: "AAMkAGR..."
  comment: "Rescheduling to later this week — new invite to follow."

All attendees are notified that the event has been cancelled. Without a comment, the cancellation goes without a message.

Delete an Event#

“Remove that old event from my calendar”

tool: manage-event
params:
  action: "delete"
  eventId: "AAMkAGR..."

Delete removes the event from your calendar. It isn’t always silent: if you organised the meeting and it has attendees, Microsoft emails them a cancellation (with no message from you). To control what they receive, use cancel with a comment instead.

Microsoft Graph doesn’t document a guaranteed recovery path for a deleted event, so don’t count on getting it back.

Preview Before You Update, Decline, Cancel or Delete#

Add dryRun: true to any action to see what it would do without changing or sending anything:

tool: manage-event
params:
  action: "cancel"
  eventId: "AAMkAGR..."
  comment: "Rescheduling to later this week."
  dryRun: true

The preview reads the event (nothing is written) and starts with DRY RUN — nothing was changed. It says exactly who would be emailed:

• cancel: “Cancels ‘Team sync’ on 3 Apr 2026, 9:00 am GMT+11:00 and emails a cancellation to 6 attendees (2 external)”, followed by your message and the attendee list
• decline: the organiser who would get your response (and whether they’re external), or that nobody is told when sendResponse: false
• delete: whether attendees get a cancellation (only for a meeting you organised that has attendees and isn’t already cancelled), or that nobody is emailed
• update: for a meeting you organise, the attendees who would be emailed an update (with the external count); with attendees, who would be added (sent an invitation) and who removed (sent a cancellation). If you change only attendees, Graph emails just those people, not the rest (unless a removed address is a distribution list, when it emails everyone). Rooms and resources count as recipients too. It says plainly when nobody is emailed: the event has no attendees, you aren’t the organiser (only your copy changes), or you changed only your own categories, reminderMinutesBeforeStart or showAs. The PATCH body that would be sent follows

“External” means an address whose domain differs from your own signed-in address. The preview also warns when Graph would refuse the action, for example cancelling a meeting you didn’t organise.

Update vs Decline vs Cancel vs Delete#

Action	Who can do it	Notifies others?	Use when
update	Organiser (full edit) / Attendee (limited fields)	Yes — attendees notified of changes	Reschedule, edit, or change attendees on an existing event
decline	Any attendee	Yes — sends decline to organiser (unless sendResponse: false)	You can’t attend someone else’s meeting
cancel	Organiser only	Yes — notifies all attendees	You’re cancelling a meeting you created
delete	Anyone	Only if you organised it and it has attendees — they get a cancellation with no message	Removing a personal event or cleaning up; prefer cancel for meetings you organised

Parameter Reference#

Parameter	What it does	Required
action	update, decline, cancel, or delete	Yes
eventId	The event ID (from list-events)	Yes
comment	Message sent with decline/cancel	No (decline/cancel only)
sendResponse	false declines without notifying the organiser (default true)	No (decline only)
subject, start, end, attendees, body, location, isOnlineMeeting, sensitivity, showAs, importance, categories, reminderMinutesBeforeStart	Event fields to change	No (update only — pass only what changes)
dryRun	Preview any action without changing or sending anything: who would be emailed, with an external count (update also lists who is added or removed, and the PATCH body)	No

manage-event is marked as destructive and open-world at the tool level, because every action can email other people: a decline goes to the organiser, a cancel or delete to the attendees, and an organiser’s update to the attendees. Clients that honour MCP annotations ask for confirmation before any action — including update. Use dryRun: true to preview any action first.

Tips#

• Use list-events first to find the event ID
• Always include a comment when declining or cancelling — it’s courteous and helps the organiser
• Delete isn’t silent for meetings you organised with attendees — they’re sent a cancellation. Use cancel with a comment when you want to say why
• On update, the attendees field is a full replacement — pass everyone who should be on the event (not just the additions). Passing attendees: [] clears the list. Existing attendees keep their type (required, optional or resource) unless you pass {email, type} to change it.

Related#

• View and Search Calendar Events — find the event ID to act on, including past events by date or subject
• Create Calendar Events — schedule a replacement meeting
• Tools Reference — manage-event