To re-order a scanned PDF you will need to make it editable first. The application you choose will depend on which operating system you are using or if your files are highly private. If you are not working on private files you can directly utilize online free OCR services Google OCR OCR X Community(desktop) OCR OCR If you are working on private files you better use offline professional OCR software s Cisdem PDF Converter OCR Element Pro FineReader Pro for Mac.