You can easily upgrade your membership by going to the drop-down menu under your user name. There is an option called payment info in this dropdown menu. Please select this option to go to your payment page. Alternatively you can go to your payment page by clicking here. On your payment info screen, you will have to select the plan you want to upgrade/downgrade to. After you select the plan, please click red button labelled Update Plan. Your plan will be updated/downgrade with immediate effect. Your current month invoice will show pro-rated cost. Your next month invoice will show the renewed cost.