Change Bulk SIP address in Exchange 2010

I tried to change bulk SIP address in my Exchange 2010 server using powershell but seem like it’s not working. Anyone able to help me ? Btw, here is my simple scripting :-

Import-Csv .\SIP_UPN.csv | foreach {Set-Mailbox -Identity $.alias -EmailAddresses @{add=$.sipaddress}}


Are you getting any error ? Can you show us the CSV with dummy values.