Hello @Kari Haapala,
Good day! Thank you for posting your valuable question on Microsoft Q&A forum.
Based on your description, I understand that in New Outlook, selecting Decline on a meeting request automatically sends the response without giving you an opportunity to add a message explaining the reason for declining.
Please let me know if I misunderstood any part of your issue or if there are additional details you’d like to share.
In New Outlook, you can’t choose a predefined reason when declining a meeting. However, you can add your explanation by replying to the invitation and emailing the organizer before declining the event.
Method 1: Decline a meeting from your inbox
1.Decline and propose a new time
Use this option if your reason for declining is related to scheduling.
- Open your Inbox and select the meeting invitation email.
- In the meeting details, click the three dots (More options) in the upper‑right corner.
- Select Propose new time > Decline and propose new time.

- In the pop‑up window, choose a new proposed time.
- Click Add a note, then enter your reason in the message field.

- Select Send to notify the organizer.
2.Decline with a note (other reasons)
Use this option if your reason is not related to changing the meeting time.
- Open the meeting invitation from your Inbox.
- Click the three dots (More options) in the meeting details.
- Select RSVP with note to organizer.
- A note field will appear under the meeting information.
- Enter your message explaining the reason for declining.
- Select Decline to send your response.

Method 2: Decline a meeting from your calendar
- Open your Outlook Calendar and select the meeting you want to decline.
- Enable the Email organizer option.
- Enter your reason in the note section.
- Select Decline to send the notification to the organizer.

I hope this helps. Please feel free to let me know if you have any additional questions or need further assistance. Thank you, and have a great day!
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