Using ListDirectory to extract file name from FTP Server

FtpWebRequest request = (FtpWebRequest)WebRequest.Create("ftp://xxxx.xxxx.com/");
request.Method = WebRequestMethods.Ftp.ListDirectory;
request.Method = WebRequestMethods.Ftp.ListDirectory;
request.Credentials = new NetworkCredential(FtpUserName, FtpPasswor);

// exception {"The remote server returned an error: (550) File unavailable (e.g., file not found, no access)."} is thrown in following statement
FtpWebResponse response = (FtpWebResponse)request.GetResponse(); 
 
Stream responseStream = response.GetResponseStream();
StreamReader reader = new StreamReader(responseStream);
Console.WriteLine(reader.ReadToEnd());
Console.WriteLine("Directory List Complete, status {0}", response.StatusDescription);
reader.Close();
response.Close();
Console.Read();