Since all recurring charges are associated with a PayPal Subscription; and every PayPal Subscription is associated with a PayPal Account; your Members will always have a PayPal Account of their own, which is tied to their Membership with you. So... a Member can simply log into their own PayPal account and cancel their Subscription(s) with you at anytime, all on their own. However, some Customers do not realize this. So, if you would like to make it clearer (easier) for Members to cancel their own Subscription(s), you can provide this Cancellation Button for them on your Login Welcome Page, or somewhere in the support section of your website. Note... you don't have to use this Cancellation Button at all, if you don't want to. It's completely optional.
Cancellation Process: Very simple. A Member clicks the Cancellation Button. PayPal asks them to log into their PayPal account. Once they're logged in, PayPal will display a list of all active Subscriptions they have with you. They choose which ones they want to cancel, and s2Member is notified silently behind-the-scenes, through the PayPal IPN service.
Understanding Cancellations: It's important to realize that a Cancellation is not an EOT (End Of Term). All that happens during a Cancellation event, is that billing is stopped, and it's understood that the Customer is going to lose access, at some point in the future. This does NOT mean, that access will be revoked immediately. A separate EOT event will automatically handle a (demotion or deletion) later, at the appropriate time; which could be several days, or even a year after the Cancellation took place.