I used the meeting planner in Outlook 2003 to create a meeting and invited some attendees. I then moved the meeting to a different time and sent an update to the attendees. I got an NDR for the update in the following form:
Your message did not reach some or all of the intended recipients.
Subject: Updated: Friday Wrap-UP
Sent: 11/16/2006 11:22 AM
The following recipient(s) could not be reached:
John Smith on 11/16/2006 11:22 AM
You do not have permission to send to this recipient. For assistance, contact your system administrator.