How to modify annotations and export it to another PDF document.

//Load the document
 PdfLoadedDocument doc = new PdfLoadedDocument(“annot.pdf");
 
//Set the color
PdfColor color = new PdfColor(Color.Green);
 
//iterate through the loaded pages
 foreach (PdfLoadedPage page in doc.Pages)
 {
 //iterate through the annotations present in respective page
 foreach (var markup in page.Annotations)
 {
 //Check  it is PdfLoadedInkAnnotation
 if (markup.GetType() == typeof(PdfLoadedInkAnnotation))
 {
 //Load the specified annotaion
 PdfLoadedInkAnnotation thisNotation = (PdfLoadedInkAnnotation)markup;
 //Modifying annotation color
  thisNotation.Color = color;                      
  }
 //Checks  it is PdfLoadedLineAnnotation
 if (markup.GetType() == typeof(PdfLoadedLineAnnotation))
  {
  //Load the specified annotaion
 PdfLoadedLineAnnotation thisNotation = (PdfLoadedLineAnnotation)markup;
  //Modifying annotation color
  thisNotation.Color = color;                  
   }
  //Checks it is PdfLoadedTextMarkupAnnotation
  if (markup.GetType() == typeof(PdfLoadedTextMarkupAnnotation))
    {
   //Load the specified annotaion
    PdfLoadedTextMarkupAnnotation thisNotation = (PdfLoadedTextMarkupAnnotation)markup;
   //Modifying annotation color
   thisNotation.Color = color;
     }
    }
 }
 
 //Creates new Pdf Document
PdfDocument nwDoc = new PdfDocument();
 
//Merging inorder to export the pdf
PdfDocument.Merge(nwDoc,doc);
 
//Save the document and dispose it.
nwDoc.Save(“annotoutput.pdf");
ldoc.Close();
nwDoc.Close();