Steps here show what mailboxes (including shared mailboxes) you have added in Outlook on your Macintosh for delegate access. Delegate access allows you to send messages or otherwise help manage the mailbox account, as long as you have been granted access by its owner.

1. In Outlook's upper left menu bar select Tools, then Accounts from the drop down menu that appears.
2. The Accounts window will open. Select the Advanced button in its lower right corner.
3. Select the Delegates tab at the top of the window that appears.
   If you are a delegate for another mailbox, it will appear in the lower half of the window under People I am a delegate for:

More Help

Allow someone else to manage mail and calendar on Microsoft's website