Open Another Mailbox in OWA Go to outlook.office365.com Enter your email address followed by your password. Note: if you're using Google Chrome as your browser and are connected to the company network, you won't need to enter your password. Once logged in, click on the avatar at the top-right of the screen Select 'Open another mailbox' In the subsequent pop-up, enter the name (or email address) of the mailbox you wish to open You now have access to another mailbox in OWAA video showing the process is below.