The floating license key registered for the current <oXygen/> instance will be released automatically when the <oXygen/> instance is closed. If you do not have Internet access to connect to the floating license server and you own also an individual license which you want to use in this case instead of the floating license, you have to open the license registration dialog again by going to Help -> Register, uncheck the Use a license server checkbox, press the Paste button to paste the individual license and press OK to switch from the floating license to the pasted individual license.