Locking code also known as machine code is a unique identification code for the machine on which UFT is installed. It is required when you want to install a seat license on your machine.
Locking code can be obtained by launching Functional Testing License Wizard from Help menu > Click on Seat License > Click “HOW CAN I GET A LICENSE KEY FILE?”
There you have a unique machine code also known as locking code. Once you get the Locking code, go to this link, paste the machine code generated above and download your new license key.
Here is a quick video