How to find delegated Send As on a user mailbox

If you would like to find delegated send-as permission on user mailbox, you can use the following powershell script :

Get-Mailbox | Get-ADPermission | where { ($_.ExtendedRights -like "*Send-As*") -and -not ($_.User -like "NT AUTHORITY\SELF") } | select Identity, User, ExtendedRights, IsInherited | FT -Wrap

For example you can use this script to find BES enabled users with delegated send as permission on BES admin user.