Using New Outlook on Windows for professional communication and productivity
Hello Nic F, my name is Jeremy and I am happy to help you today.
Do you use both outlook on the web and the desktop app?
If you are using both there is a sync feature that may be causing the issue.
Are you trying to make the change on outlook.com?
Try making the change on the desktop app.
If you have automatic syncing set you will need to change it on the desktop version.
Thank you for reaching out to the community forums and have a good rest of your day.
Regards,