Message / Action / Cancel

 ZCONNECT / RFC:  Sends out a cancel message for the   
 selected newsgroup message, as long as it was written 
 by you. In this way a message already sent out can be 
 deleted. The cancel message takes the same route as   
 the original, and everywhere they meet, the original  
 is deleted. (It does not prevent the original being   
 seen, before the cancel message arrives).             
                                                       
 See also /Config/Opt./Nets/Cancel-Messages.           
                                                       
 MausNet:   This only cancels an already sent          
 message, if it has not gone from the server into the  
 net.