Office 365 – Postfachfreigabe – SendAs
$cred = Get-Credential
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://ps.outlook.com/powershell -Credential $cred -Authentication Basic -AllowRedirection
import-PSSession $Session
Add-MailboxPermission -identity FREIGABEUSER@DOMAIN.DOM -user USER@DOMAIN.DOM -AccessRights FullAccess
Add-RecipientPermission FREIGABEUSER@DOMAIN.DOM -AccessRights SendAs -Trustee USER@DOMAIN.DOM