According to Microsoft Teams support documentation, all registered attendees will automatically receive an email notifying them that the date or time of the event has changed.
To inform presenters:
Changes to any of the basic webinar info (title, presenters, date, and time) will be emailed to the presenters.
- In your calendar, double-click the webinar event.
- Make your changes.
- Select Send update in the top right of the page.
To inform registered attendees:
Attendees will receive an email informing them about changes to the date or time of the webinar; they won't get notified about any other changes.
- In your calendar, double-click the webinar event.
- Select Customize registration form.
- Select Edit in the upper-left corner of the form.
- Make your changes.
- Select Save in the upper-left corner of the form and in the Send update? box, select Send.
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Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.