qwinsta /server:servername
Results:> qwinsta /server:Blackjack
SESSIONNAME USERNAME ID STATE TYPE DEVICE
console 0 Conn wdcon
rdp-tcp 65536 Listen rdpwd
rdp-tcp#70 Tim 1 Active rdpwd
rdp-tcp#75 Ron 2 Discon rdpwd
Ron's session is disconnection as the status tells us. To terminate Ron's session I would type this:
rwinsta /server:Blackjack 2
The commands stand for:qwinsta = Query WINdows STAtion
rwinsta = Reset WINdows STAtion