This confluence article walks through the process of changing the auto-reply message for a shared mailbox
GAIN ACCESS TO THE SHARED MAILBOX
1. Ensure you are added to the shared mailbox (This is done through admin > Microsoft Exchange > Mailboxes > find mailbox and select edit > Delegation > Read and Manage Access
OPEN MAILBOX IN OUTLOOK
*If you have already logged into your account on the outlook app you will need to go through the following steps to open the mailbox properly
Once Outlook removed:
EDITING THE AUTO-REPLY MESSAGE
i.e. for the example above you would double click on 'Staff Absentees Auto Reply'
5. This should open up the email containing the current auto reply message
6. Edit the message
7. Save the new message – Select File > Save
8. Once saved select finish
9. A message indicating the rule will be applied to every message will pop up - Select Yes
You have now changed the auto reply