You need to send all email for an existing Exchange mailbox to another address in Microsoft Office 365.
This can be done by an Office 365 site administrator on behalf of another user (e.g., a user that is home sick for an extended amount of time).
- Log in to www.office365.com as a user with admin privileges. Click the “Manage” Link under the Exchange subheading (highlighted below)
- On the “Mailboxes” page that opens, next to the “Mail > Options” breadcrumbs is a select field. Choose “Another user…”, the select the user whose mail needs to be forwarded.
- This will open the account management page of OWA as that user. Click the “Connected Accounts” tab.
- At the bottom of the page is the Forwarding controls. Enter the new address that should receive this user’s mail; this is the same for both external and internal forwards. If the original recipient should also get a copy of the message that was forwarded make sure to check the “Keep a copy of forwarded messages” (usually checked by default).
- Click the “Start Forwarding” button to save the changes.