If you offer a variety of subscriptions, subscribers might want to upgrade or downgrade them. For example, if your service offers stock market reports, a subscriber might like to upgrade to a subscription that offers more reports.
The Amazon Simple Pay system does not directly support the modification of an active subscription, but there is a way to offer this functionality. You can create a new subscription using Amazon Simple Pay and then use the Amazon Flexible Payments Service CancelSubscriptionAndRefund API to cancel the current subscription.
Modifying a Subscription using CancelSubscriptionAndRefund
Create a modify subscription button that sends the same request that the subscription button sends.
All your buttons should have a unique value for the
Parse the subscription modification response. If Amazon Payments returns success, and if it represented a modification, send a
|3||Amazon Payments sends email messages for the creation of the new subscription as well as the cancellation of the older subscription to both the subscriber and seller.|