You can cancel your subscription by going to the billing tab inside your account settings.
Canceled subscriptions stay active until the next billing cycle date. The user will not be charged again. The billing page will indicate that the subscription will be canceled by displaying the following message in red: “Your subscription is set to cancel on MM/DD/YYYY.”
Upon the beginning of the next billing cycle, you will be asked to convert over the account to the free individual plan. After converting, you will be able to continue working on the projects you own, but any collaborators will only be able to observe (not edit) any projects you own that they have access to.