The SendSessionMessage method sends the specified message to the specified Terminal Services session on the specified server. This may be used to notify users of server events (for example, reboot) that will affect their sessions.
Not implemented, because it is not possible to roll back this action.
WTSSendMessage
<request> <procedure> <execute namespace="Terminal Services Provider" procedure="SendSessionMessage"> <executeData> <server>TheServer</server> <sessionId>2</sessionId> <message>Session ending. Please log off.</message> </executeData> </execute> </procedure> </request>