For this procedure to work, the Resource Account's owner or administrator must use the Exchange Account Manager to grant you Access rights.

1. Login into Outlook Web app. 
2. In the red, Cornell-branded Office 365 navigation bar, click your photo (or the generic person icon; it's the thing to the left of the gear icon), then select Open another mailbox.
3. In the small open another mailbox dialog box, type all or part of the email address of the account you want to open. Outlook on the Web will look for matching entries in your contacts and the directory as you type. Select the desired entry from the displayed list.
4. Click Open.

The Resource Account will open in a separate browser tab or window, allowing you to have multiple accounts open at the same time.