The new version of Office 365 now allows you to manage mailbox and group permissions directly from the web interface. This includes Full Access/Read Only permissions and Send As/Send On Behalf of rights.
It’s still not very easy to view who has access to what mailboxes or groups, but that is where our Office 365 reporting application can help you.
Log in to the new portal and click Exchange from the Administration Menu.
You will see all your Mailboxes listed. Select the mailbox that you wish to modify the permissions on and click the pencil icon. You can now click the Mailbox Delegation link to set the Send As, Send on Behalf of and Full access permissions for this mailbox.
Mailbox Send As and Send On Behalf Of permissions in Office 365 Wave 15
Mailbox Full Access Permissions in Office 365 Wave 15
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