function cancelSell() {
       if( now <= passoverStartTime ) throw; 
     
        if( sellerNumOpenDeals[ msg.sender ] == 0 ) throw; 
        uint payment = sellerNumOpenDeals[ msg.sender ] * buyerBonus;
        sellerNumOpenDeals[ msg.sender ] = 0;
        if( ! msg.sender.send( payment ) ) throw;
        
        CancelSell( msg.sender, payment, now );
    }