The first step is to email the lockcode to the email@example.com. If you have an email client installed simply hit the button and this will generate the email for you. Alternatively copy the code and create the email manually.
The HelpDesk will reply with a revoke code, just paste this code into the dialogue box and click 'Next'.
The final step is to send the PC Moving Code to the support team. Again clicking the button will generate the email for you. The support team will reply confirming the licence has been removed.