Note: Add a reference in your project to PDFresizeNET To do this:   a. On the Project menu, click Add Reference;   b. On the .NET tab, locate PDFresizeNET and then click Select;   c. Click OK in the Add References dialog box to accept your selections.

   PDFresize.Neevia NVresize = new PDFresize.Neevia();
   int retVal;

   NVresize.Paper = "letter";
   NVresize.Orientation = 2;
   NVresize.Scale = true;

   retVal = NVresize.ResizePDF(@"c:\in.pdf",@"c:\out.pdf");
   if (retVal != 0) {
     MessageBox.Show("Error code = " + retVal.ToString());
   } else {
     MessageBox.Show("Done");
   }