When you attempt to change a SQL Server 2008 R2 server collation using the instructions in Setting and Changing the Server Collation (shown below), this may fail with an invocation error.
Setup /QUIET /ACTION=REBUILDDATABASE
/INSTANCENAME=InstanceName /SQLSYSADMINACCOUNTS=accounts
/[ SAPWD= StrongPassword ] /SQLCOLLATION=CollationName
You could try resolving this issue by running the command using setup.exe from the installation media.