Shared Mailbox - Send as another user

Question

I would like a user to be able to reply to messages in a shared mailbox but show as another member of that shared mailbox. Is this possible?

Example, users A, B, and C are members of a shared mailbox. User A would like user's B and C to be able to respond to messages in the mailbox and show the response as coming from user A.

Answer 1

You will need to give them SEND AS perms to B and C to send as UserA

Exchange on-prem:

https://learn.microsoft.com/en-us/exchange/recipients/mailbox-permissions?view=exchserver-2019#use-the-eac-to-assign-permissions-to-individual-mailboxes

Exchange Online:
https://learn.microsoft.com/en-us/exchange/recipients-in-exchange-online/manage-permissions-for-recipients#use-the-eac-to-assign-permissions-to-individual-mailboxes

Then UserB or C can add User A to their FROM and send as that user.
Ensure User A is not hidden from the Address Book and If using Outlook in cache mode, wait 24 hours for the change to sync to the workstation.