You can change the registration key you use on a BIG-IP VE system and go through the relicensing process (generate dossier, upload dossier to F5 License Server, download new license, and install on BIG-IP). Please be aware that traffic processing will stop during relicensing, but it sounds as if the systems are not working right now anyway. Using the Configuration utility is the easiest way ( K7752: Licensing the BIG-IP system). If you no longer have GUI access to the BIG-IP system though, you can relicense from the command line. See K2595: Activating and installing a license file from the command line.