To extend your membership time, you must purchase the new subscription through the website while logged into your username. The new subscription will not begin until your current subscription has completed.
If you have a current promo code, you can apply it to the order during checkout to receive the discount. Please note, any subscription you purchase will be set to renew automatically at the original purchase price, including any discounts that may have been applied.
You will see the new renewal date reflected from your account page. If you cancel the auto renewal from your account page it will expire at the end of the new term.