How to shrink the content of existing PDF document?

// Create a new instance of PdfDocument class.
PdfLoadedDocument document = new PdfLoadedDocument("../../Data/sample.pdf");
 
PdfTemplate template = document.Pages[0].CreateTemplate();
 
//Newly created document
PdfDocument doc = new PdfDocument();
PdfPage page = doc.Pages.Add();
 
// Create Pdf graphics for the page.
PdfGraphics g = page.Graphics;
 
// Create a solid brush
PdfBrush brush = new PdfSolidBrush(Color.Black);
 
// Set the font.
PdfFont font = new PdfStandardFont(PdfFontFamily.Helvetica, 20f);
 
// Draw the text.
g.DrawString("Hello world!", font, brush, new PointF(20, 20));
 
// Draw the PDF template with reduced size
g.DrawPdfTemplate(template, new PointF(0, 40), new SizeF(500, 500));
 
// Save and close the document.
doc.Save("Sample.pdf");
doc.Close(true);
document.Close(true);