- Sign in to your personal account in Outlook Web App at https://outlook.office365.com.
- In the upper right of the screen your name should be listed. Click your name and select "Open another mailbox..."
- Type in the email address of the other mailbox that you want to open. If you have permission to that mailbox, it should now appear alongside your other folders.
Additional information on this process may be found here.
Note: You will receive the following error if you log in to the Outlook Web App with the account you are trying to access instead of your personal account:
"Just so you know... You should be seeing tiles for each of your online apps. Contact your help desk or IT department. They can help you get up and running."