I keep tripping over one step in the moderated folder settings for Outlook public calendars. In these cases, I want to set up a moderated public folder (this time with a custom form) in order for individual to schedule resources but allow a coordinator to review and approve those changes. This calls for a moderated folder, but I always trip up over one setting when I try to create a custom response to the user. This leads to the dreaded “Unable to save the moderated folder changes” message. I finally rediscovered the solution for the third time in as many years. Here is the KB article that explains it. Mail-enable the folder in the Exchange System Manager, go to Directory Rights, and then give the folder moderator “Send As” permission.
One additional piece of information was needed for my feeble mind: the folder moderators are the individuals who should get Send As privileges, since essentially they are sending the calendar object to the user as the public folder.