This is not possible, since this is the way the small square modules are arranged that determines this action (the module arrangement encodes the data). To change this action, one would need to rearrange the modules. This implies physically modifying the QR Code if it has been printed.
As for any technology, there are stories of QR Codes being used maliciously. It is important to know what is made-up and what the real risks are. Here is what you need to know on the subject.
Hacking a QR Code means that the action triggered would have been modified through a manipulation.
This is not possible, since this is the way the small square modules are arranged that determines this action (the module arrangement encodes the data). To change this action, one would need to rearrange the modules. This implies physically modifying the QR Code if it has been printed.
QR Codes cannot be hacked, but it is possible to replace a QR Code with another or to create a QR Code that will redirect to malicious content.
A QR Code can be created that redirects to malicious content (websites that download malware, with illegal content, etc.). You must be careful when scanning a QR Code, not to become a victim of these malicious QR Codes.
On a computer, you don't click on a link from a non-trusted website; you must apply the same rule for QR Codes: don't scan a QR Code if you have doubts about it. Besides, most QR Code readers now actually display the link address before opening the web browser.
Phishing targets victims by masquerading as a trustworthy entity. In the case of QR Codes, it means replacing the QR Code on a poster with another QR Code (e.g., a sticker). Users would then think they are scanning the QR Code of a company they trust, but would be redirected to malicious content.