How do you redirect all emails on a Shared Mailbox? 

Firstly, you must open the Shared Mailbox:

1. Log into Outlook Web App (OWA)
2. Click your Profile/Portrait in the top right corner
3. Click Open another mailbox...
   
4. Enter Shared Mailbox name or email address
   NOTE: The system will auto-populate options for you to choose from once you start typing. If nothing appears either you have the mailbox name wrong or you don't have access.
5. Click Open
   

Now that you are in the Shared Mailbox:

1. Click Settings (the cog) top right
2. Click Options
   
3. Click Inbox and sweep rules
4. Review any existing rules to see if they require modifying or select + to add a new rule  
   
5. Enter a Name for the new redirect rule.
6. Select [Apply to all messages] from the dropdown under When the message arrives, and it matches all of these conditions
7. From the dropdown Do all of the following select Forward, redirect, or send and click Redirect the message to

   

8. Enter the name of the mailbox (it can be the email address) that all emails should be forwarded to.
9. Click the magnify glass to search
10. Click + to add the mailbox
11. Click Save
    
12. Click Add action under Do all of the following section
13. From the additional dropdown under Do all of the following select Move, copy, or delete and click Delete the message.
    
14. If prompted with a Warning, tick Don't show me this message again
15. Click OK
    
16. Review the rules and click OK
    
17. The inbox rules are now displayed for the mailbox and they are active.
    NOTE: That under 'Do the following'… it may appear that it is going to delete the message first, then redirect it. This is correct. 
    NOTE: If you need to modify or delete this rule you may do so through the pencil icon for editing, or trash icon to delete the rule. Wait at least 10-15 minutes before testing the rule as changes need to be synced. To test send an email to the original shared mailbox. It should automatically redirect to the nominated mailbox - this test should be done by a person other than the person setting up the redirect. The test will not work for the person carrying out the redirection. Putting Out of Office on through Outlook Web App (OWA)
    

NOTE: It is recommended that monthly maintenance on purging out the sent and deleted items of the redirected shared mailbox occurs.  As the email still resides within these areas after it forwards to the redirected/nominated mailbox.

Please see putting an auto reply/out of office on through Outlook Web App (OWA) page to notify people of the change in email address.