Send On Behalf access allows a user to send mail on behalf of the mailbox owner.

Figure 1: Send On Behalf access can be assigned from ADUC | recipient properties | Exchange General | Delivery Options, or by the mailbox owner using Microsoft Outlook
Here’s a script that lists all users with delegates.
File: listDelegates.zip
Could you adapt it so that the script does an export to a testfile instead of spawning popups?
[…] SCRIPT: List Delegates With Send On Behalf Access […]