1. Login to your Office365 Outlook web portal here: https://outlook.office365.com
2. Click on any email in your inbox
3. Look out to the right-hand side of the screen to find the “Reply all” button. It looks like this:
4. Click on the down arrow beside “Reply all” to open a menu
5. Hover over the “Change Default” option to open a new menu
6. Select “Reply”
7. Your default setting should now show “Reply” instead of “Reply all”