We only store the bare minimum. When a packing slip is selected, it is scanned for only particular data like order number and zip code as it is needed for looking up and generating a barcode. The packing slip is not stored anywhere.
When the packing slip is processed. All we do is modify the file by swapping out or replacing text. Then the file is downloaded back out to print and store if needed.
Packing slips cannot be re-downloaded as we do not store them. If a packing slip needs to be reprinted, remove the old one and re-upload the packing slip WITHOUT a barcode.
Just upload the same original packing slip twice. Every time a packing slip is uploaded a new barcode is generated. On the dashboard they will be grouped together and when a buyer looks up their order number they will see tracking for both envelopes.