Exchange Online mailboxes support SendAs, Send on Behalf Of, and FullAccess permissions. A previous script focused on the FullAccess permission. This version covers all three. It’s also a good example of how you need to pay attention to property sets when writing PowerShell code to use the new Exchange Online REST-based cmdlets.
https://office365itpros.com/2020/03/25/reporting-exchange-online-fullaccess-sendas-sendonbehalfof/
