Reorder the pages of a PDF
Put the pages in a new order
Write the new order, every page once: 10, 1-9 moves the last page to the front. A page named twice, or one forgotten, is named back to you before anything is made, so a reordered file never quietly loses or duplicates a page.
Bookmarks and links follow their pages to where they now stand.
Reorder pages now — it opens the tool, with nothing to install.
What it never does
No page is drawn again. Its text, its drawings and its images are the same stored bytes as in the file it came from, and that is checked on every page before the new file is offered: a page that did not come across byte for byte means no file at all. The file you started from stays as it was, and so does every correction on it.
The record
The new file says how it was made: which pages, from which files, in what order and turned how far, in the record it carries and in your account's trail. Files are deleted after 90 days, or whenever you erase them.