The below is the script which can be used to assign the sitecode for the SCCM Client PC remotely. There will be a scenario of changing the sitecode in the client computers after implementation of new SCCM server with different sitecode, or may be moving all the users from the earlier SMS to SCCM2007 environment of different sitecode. In this case, we can make use of the below VBScript to change the sitecode in the configuration client (SCCM Client) in all the clients remotely. The below scripts can be deployed using the GPO via Logon Script or using the remote execution of the scripts or even use remote script execution tools. The permission for the execution of the script in the client PC is obvious, for better practice can make use of the same SCCM admin account, which in turn will have the appropriate permission for the script execution.
'replace with your Site Code
sSiteCode = "NEWSITECODE"
sMachine = "."
set oCCMNamespace = GetObject("winmgmts://" & sMachine & "/root/ccm")
Set oInstance = oCCMNamespace.Get("SMS_Client")
set oParams = oInstance.Methods_("SetAssignedSite").inParameters.SpawnInstance_()
oParams.sSiteCode = sSiteCode
oCCMNamespace.ExecMethod "SMS_Client", "SetAssignedSite", oParams
Save the above file with the extension .vbs and replace "NEWSITECODE" with your sitecode accordingly.