how to find a character and replace the entire line in a string vb.net

If Svr.Pending = True Then
           massage = " "
           cln = Svr.AcceptTcpClient
           Dim write As New StreamReader(cln.GetStream)
           While write.Peek > -1

               massage = massage + Convert.ToChar(write.Read()).ToString
           End While


           TextBox2.AppendText(out)

       End If