Add a New Attendee to a Meeting Without Email Others Using Power Automate

One of my colleagues recently asked for help with a tricky scenario. He runs a webinar where participants register at different times, and every time a new participant signs up, he wants to send them the meeting link. However, he doesn’t want Outlook to continue emailing all the previously registered attendees repeatedly.

Usually, if you use the Update Event action from Outlook Connector in Power Automate to add someone new, Outlook sends an update email to everyone in the meeting. To avoid spamming the entire group, we can use the Send an HTTP Request action from Outlook Connector, which allows us to add the new attendee discreetly.

In this tutorial, I will show you how to add a new attendee to an existing Outlook calendar event using Power Automate without triggering an email to the existing participants.

Add a New Attendee to a Meeting Without Emailing Others

Before we build the flow, create a meeting in Outlook that we can update later.
For example, I created a meeting named Participant with the following details:

• Title: Participant
• Date & Time: pick any future date/time
• Add at least one attendee (optional, just for testing)

Once the meeting is saved to your Outlook calendar.

Steps to Create the Flow:

1. Go to Power Automate and click Create -> Instant Cloud Flow. Select Manually trigger a flow as the trigger. Click + Add an input and add the following inputs:
   • AttendeeEmail (Type: Email)

2. Add Get Events (V4) Action to Retrieve Calendar & Event ID and provide the following parameters:
   • Calendar Id: Calendar
   • Filter Query: subject eq ‘Participant’
   • Top Count: 1

This action searches your Outlook calendar for the meeting named Participant and returns the most recent event that matches.

3. Add a compose action and provide the following expression to get the Calendar ID:

actions('Get_events_(V4)')?['inputs']?['parameters']?['table']

4. Add another compose action for getting the event ID to do this, give the following expression:

first(body('Get_events_(V4)')?['value'])?['id']

These two Compose actions will provide the dynamic values you’ll reference in the next step.

5. Then add a Send an HTTP request action from Office 365 Outlook Connector with the following parameters:
   • URI:

https://graph.microsoft.com/v1.0/me/calendars/@{outputs('Compose_|Calendar_ID')}/events/@{outputs('Compose|_Event_ID')}

Replace Compose_Calendar_ID and Compose_Event_ID with the actual names of your Compose actions.

6. Method: Get

6. Add an Initialize variable and provide the parameters below to store all attendees’ details in an array:
   • Name: varAttendees
   • Type: Array
   • Value:

body('Send_an_HTTP_request')?['attendees']

7. Add an Append to array variable action and provide the parameters below to add the new attendees:
   • Name: Select varAttendees
   • Value:

{
  "type": "required",
  "status": {
    "response": "none",
    "time": "0001-01-01T00:00:00Z"
  },
  "emailAddress": {
    "name": "Lidia Holloway",
    "address": "@{triggerBody()?['email']}"
  }
}

Note: I have added the name manually here; you can also add it in the input parameters.

8. Again, add the Send an HTTP request action from Office 365 Outlook Connector with the following parameters:
   • URI: Same URI as above (Send an HTTP request action).
   • Method: PATCH
   • Body:

{
"attendees": @{variables('varAttendees')}
}

This updates the meeting to include the new attendee specified in the AttendeeEmail input without sending an update email to the existing participants.

Run the Flow and Check the Output

1. Click “Save” in the top-right corner of the Flow Designer. Click Test -> Manually -> Run flow.
2. Provide a test email in AttendeeEmail.

3. Open the Outlook meeting to confirm that the new attendee was added silently.

We can use the Send an HTTP request action instead of the standard Update Event action. You can quietly add new attendees to an existing Outlook meeting without triggering update emails to everyone.

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