Downloading File gives an error The process cannot access th

 if (!File.Exists(FlagFilePath))
                {
                    Debug.WriteLine("Trying to download sales data file ");

                    SessionOptions sessionOptions = new SessionOptions
                    {
                        Protocol = Protocol.Sftp,
                        HostName = ConfigurationManager.AppSettings["SFTPDomain"],
                        UserName = ConfigurationManager.AppSettings["SFTPUser"],
                        Password = ConfigurationManager.AppSettings["SFTPPass"],
                        PortNumber = Convert.ToInt32(ConfigurationManager.AppSettings["SFTPPortNumber"]),
                        GiveUpSecurityAndAcceptAnySshHostKey = true,

                    };

                    using (Session session = new Session())
                    {

                        //Attempts to connect to your SFtp site
                        session.Open(sessionOptions);

                        //Get SFtp File
                        TransferOptions transferOptions = new TransferOptions();
                        transferOptions.TransferMode = TransferMode.Binary; //The Transfer Mode - Automatic, Binary, or Ascii 
                        transferOptions.FilePermissions = null;  //Permissions applied to remote files; 
                        transferOptions.PreserveTimestamp = false;  //Set last write time of destination file 
                        //to that of source file - basically change the timestamp to match destination and source files.    
                        transferOptions.ResumeSupport.State = TransferResumeSupportState.Off;
                        //SFTP File Path
                        Sftp_RemotePath = ConfigurationManager.AppSettings["SFTPFileName"].ToString();
                        //Delete File if Exist
                           if (System.IO.File.Exists(FilePath))
                        {
                            System.IO.File.Delete(FilePath);
                        }
                        //the parameter list is: remote Path, Local Path with filename 
                        TransferOperationResult transferOperationResult = session.GetFiles(Sftp_RemotePath, FilePath , false, transferOptions);
                    
                        //Throw on any error 
                        transferOperationResult.Check();
                        Debug.WriteLine("Downloaded fresh sales data file!");
                    }
                }

{WinSCP.SessionRemoteException: Can't create file 'D:\TESTING\SFTP\Data.csv'. ---> WinSCP.SessionRemoteException: System Error.
      Code: 32.
    The process cannot access the file because it is being used by another process
       --- End of inner exception stack trace ---
       at WinSCP.OperationResultBase.Check()
       at JetStarAPI.Models.SFTPClient.DownloadFile(String FilePath) in D:\TESTING\SFTP\Models\SFTPClient.cs:line 65}

  transferOperationResult.Check();

  TransferOperationResult transferOperationResult = session.GetFiles(Sftp_RemotePath, FilePath+Path.GetRandomFileName() , false, transferOptions);