Docotic.Pdf library can be used to split and merge PDF documents.
You can append one PDF document to another
whenever you need to combine documents. And, of course, the library can
copy PDF pages
from an existing document to a new one.
You can add new pages to PDF documents or remove existing ones with the help of the library.
Take a look at samples that show how to add new pages
and insert or remove existing PDF pages.
You can also change order of pages in your PDF documents.