RefreshTorIdentity.cs

public void RefreshTorIdentity()
{
    Socket server = null;
    try
    {
        IPEndPoint ip = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 9151);
        server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        server.Connect(ip);
        server.Send(Encoding.ASCII.GetBytes("AUTHENTICATE \"johnsmith\"" + Environment.NewLine));
        byte[] data = new byte[1024];
        int receivedDataLength = server.Receive(data);
        string stringData = Encoding.ASCII.GetString(data, 0, receivedDataLength);
        server.Send(Encoding.ASCII.GetBytes("SIGNAL NEWNYM" + Environment.NewLine));
        data = new byte[1024];
        receivedDataLength = server.Receive(data);
        stringData = Encoding.ASCII.GetString(data, 0, receivedDataLength);
        if (!stringData.Contains("250"))
        {
            Console.WriteLine("Unable to signal new user to server.");
            server.Shutdown(SocketShutdown.Both);
            server.Close();
        }
    }
    finally
    {
        server.Close();
    }
}

You could make line 9 contain "your_password" instead of "johnsmith" so it matches the "tor.exe –hash-password “your_password”" from the blog.