Let say if in any situation you have been asked to set the Out Of Office reply on particular mailbox , you have to go through a number steps after taking the full access on that mailbox but Exchange 2010 new cmdlets help and makes Exchange Admins job easier by using these cmdlets

So if you want to set the automatic reply for user USER1 , this is how you can do it – First run the Get cmdlet to see if he existing settings

[PS] C:>Get-MailboxAutoReplyConfiguration -Identity 'user1'

RunspaceId       : 84fb5949-eeb8-4b12-ab02-50017ca4ebbe
AutoReplyState   : Disabled
EndTime          : 2/18/2012 4:00:00 PM
ExternalAudience : All
ExternalMessage  :
InternalMessage  :
StartTime        : 2/17/2012 4:00:00 PM
MailboxOwnerId   : TECHIESONLY.COM/Users/User1 Team
Identity         : TECHIESONLY.COM/Users/User1 Team
IsValid          : Trues
C:>Set-MailboxAutoReplyConfiguration -Identity 'User1' -StartTime '2/17/2012 16:47'-AutoReplyState Enabled -EndTime '2/19/2012 07:00'
-InternalMessage 'User1 is on vacation and will respond to your message after she returns on FEB 19'-ExternalMessage 'User1 is on vacation'
-ExternalAudience 'All'

Now run again 

[PS] C:>Get-MailboxAutoReplyConfiguration -Identity 'user1'

User-end view via OWA

Cheers :)