This article describes how to add someone else's mailbox to your existing Outlook profile that's already connected to a hosted Exchange mailbox.
WARNING: You need to have appropriate permissions to the mailbox in order to be able to add it. If you need to adjust permissions, please open a support ticket.
WARNING: The mailbox you are adding should not be hidden from the Global Address List (GAL).
Adding someone else's hosted Exchange mailbox to your Outlook profile
- Modify the settings of your profile. Navigate to File > Info > Account Settings > Account Settings > highlight your profile and click Change.
- Navigate to More Settings > Advanced tab > Add... and type in email address that you want to add as an additional mailbox.
- Click OK twice.
- Click Next.