Changing or cancelling your plan
Through the billing portal, any time. Access runs to the end of the period.
Use "Manage subscription" on your account page. It opens our payment processor's portal, where you can change plan, update the card, or cancel.
Cancelling keeps your access until the end of the period you have already paid for. After that the account moves to the free plan — you keep your library within the free storage quota, and you keep any credits you bought.