• 'netdom' is for machines on an AD domain
• Use quotes around 'newname'
• Reboot afterwards

wmic computersystem where caption='currentname' rename 'newname'

netdom renamecomputer %COMPUTERNAME% /Newname "NEW-NAME"

Windows 2008/2012:

netdom renamecomputer "$env:COMPUTERNAME" /Newname "NEW-NAME"

Then reboot to activate the new hostname:

shutdown -r -t 0

WHS script:

Set objWMIService = GetObject("Winmgmts:root\cimv2")

For Each objComputer in _
    objWMIService.InstancesOf("Win32_ComputerSystem")

    objComputer.rename "NewComputerName", NULL, NULL 
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