I am pretty sure (but not positive) that you would have to stop a recurring subscription within the billing processor's website... As its the billing processor that keeps track of a recurring subscription, and re-charges the subscriber... it only lets aMember know the result. aMember doesn't initiate the recurring payment itself
It depends on payment processor and who does the rebill. If amember does the rebill (i.e. amember is storing the cc info locally) then all you would have to do is change the product to be non-recurring. Amember via cron will try and find expired payments for configured payment plugins. It then uses the payment record to back-reference the product. If the product is not set to recurring then it skips that expired payment record and moves on to the next one. If your using PayPal or CCBILL or something similiar where they do the rebill and notify amember of the rebill then it is up to the user to cancel the rebill. Jimmy