Booking Delegation Vs. Classic Delegation
Calendar delegation can be assigned in two different ways, each for a specific scenario. However, any mailbox, usually rooms, can be assigned both and this causes confusion when managing delegation of rooms or resources. What’s the difference and why?
Read more at source: http://blogs.technet.com/b/exchange/archive/2015/06/29/booking-delegation-vs-classic-delegation.aspx