we have a room calendar for meetings. I have a user that is the delegate, when user "A" setups a meeting including user "B" and sends the request, User "B" gets an email for the meeting, before the delegate accepts or declines the meeting. Where in Exchange 2013 is the setting so User "B" would not get a meeting request until the meeting is Accepted?

Does the email that User B receives say the meeting is "tentative"?

No, I get the meeting request right away, I can accept or decline, before the delegate does anything. 

So in the properties of the room mailbox, under 'booking delegates', for "Booking requests" you have chosen "Select delegates who can accept or decline booking requests"?  Then under "Delegates", you have a user listed? Then in the 'mailbox delegation' then "Send on behalf", you should see the same user account that is listed as a delegate? Just confirming the basics.

Try this:

Set-CalendarProcessing -Identity "ROOM CALENDAR NAME HERE" -AllBookInPolicy $false

Run that, then try to book the room again from User A and see if User B gets it w/out approval from the delegate.  Let us know how it worked out.

It is set to "False" (see below). 

[PS] C:\Windows\system32>Get-CalendarProcessing -Identity auditorium_lobby | select *inpolicy

BookInPolicy                                                AllBookInPolicy RequestInPolicy                                        AllRequestInPolicy
------------                                                --------------- ---------------                                        ------------------
{}                                                                    False {}                                                                   True

yes, that is how the resource is setup

What updates have you applied to your server?  CU level?

Version 15.0 (Build 913.22)

Run the following command and reply with the output please.

Get-CalendarProcessing "room name" | FL

Which settings would you need?

I was just looking to see all of the settings at one shot to review them.  If you're not comfortable posting it, that's fine.