Accessing a shared mailbox is possible in instances when multiple individuals need to either retrieve mail or send out as the mailbox in question.
To accomplish this, first ensure that you have access to the mailbox in question. Check with COE IT first (firstname.lastname@example.org) or x4444.
For Outlook 2011 on the Mac, go here.
For Mac Mail.app, go here.
For Outlook 2013 on Windows, go here.