The current idea is that each individual would post to the calendar with his or her proposed leave.
The entry would go to the manager for moderation; it wouldn't appear on the calendar until the moderator-manager approved it.
I can see how to set up a moderated calendar, but not how to approve items once they go to the manager. I've tried the Outlook help and the MS Office site, but haven't found any useful information. They both explain how to set up a moderated folder, but not how to approve the items.
Alternatively, is it possible to set up a calendar so that people can request time, but the entry doesn't appear on the calendar until the owner approves it?