To change from a monthly to annual plan, go to the 'my account' section of our site, and choose 'my subscription' from the left hand menu.
Click the 'change plan' button.
On the next screen, click the 'choose option' drop down box, and select 'annual'.
Click 'sign up now', and proceed to pay.
Your monthly plan will continue until the end of the current subscription period, at which time, you will then be switched to the annual plan.