None.
You must send this to each PC where you want to cancel actions.
The following hotkey cancels actions on the local PC:
<Hotkey F1> <SendPC local> <Cancel>
The following hotkey cancels actions on a remote PC:
<Hotkey F1> <SendPC 192.168.1.106> <Cancel>
The following hotkey cancels actions on three PCs:
<Hotkey F1> <SendPC local> <Cancel> <SendPC 192.168.1.103> <Cancel> <SendPC 192.168.1.105> <Cancel>