When you create a PDF out of bits and pieces of other PDFs (as described in Combine Existing PDFs), chances are good that you will have to make some adjustments to the pages that you have brought together. For example, you may have a page containing a figure that needs to be rotated from landscape to portrait orientation, or you may have a range of pages that need to be reordered, or you may have some legal-size pages that need to be cut down to letter-size.
PDFpen can help you with all of those tasks.
The Thumbnail sidebar and your preferred pointing device are the tools you need to rearrange pages in a PDF.
Follow these steps to move a page from one place to another in a PDF:
Choose View > Thumbnails ...