CmdID / PowerShell / Cmdlets / Unlock
Unlock-WmsSession
Unblocks a user for desktop use. Windows Server PowerShell reference
From the Windows Server PowerShell reference 3 parameters Its page in the reference
Parameters
-AllIndicates that this operation applies to all sessions on the target host.-Server, -ComputerNameSpecifies the fully qualified host name of the MultiPoint Server that is the target of the command.-SessionIdSpecifies the session ID.