How Do I Use This Code to get rdlc in pdf

private void CreatePDF(string fileName)
 {     // Variables    
 Warning[] warnings;   
  string[] streamIds;  
   string mimeType = string.Empty;  
   string encoding = string.Empty;   
  string extension = string.Empty;      
   // Setup the report viewer object and get the array of bytes  
   ReportViewer viewer = new ReportViewer();    
 viewer.ProcessingMode = ProcessingMode.Local;   
  viewer.LocalReport.ReportPath = "RmsReport.rdlc";      
   byte[] bytes = viewer.LocalReport.Render("PDF", null, out mimeType, out encoding, out extension, out streamIds, out warnings);      
   // Now that you have all the bytes representing the PDF report, buffer it and send it to the client.   
  Response.Buffer = true;     Response.Clear();     Response.ContentType = mimeType;  
   Response.AddHeader("content-disposition", "attachment; filename=" + fileName + "." + extension);   
  Response.BinaryWrite(bytes); // create the file  
   Response.Flush(); // send it to the client to download }
still report is showing excel,word format