You can use Mapsoft’s PDFSplitter tool to split an existing PDF file into separate PDF files.
You can choose to split the file into a new file for each individual page within the existing file, or you can specify the range of pages which should go into each new document.
In this way it is possible just to extract those pages you require from a large document and ‘leave’ the rest.
If you wish, you can re-split a file repeatedly: the resulting split files will be overwritten.
You choose if you want existing bookmarks to be retained or not.