You can’t change the information that is encoded in a barcode after it has been printed. Rather than having to change the QR code on your pack, you can dynamically change the digital content that the QR code connects to.
QR codes powered by GS1 are encoded with a URL and a GS1 Identifier, typically the GTIN. Because you are essentially identifying a product rather than just encoding a website address, you can redirect to multiple or updated pieces of online content in a relatively straightforward way by using a resolver.