Paypal (+ Paypal IPN) - how to change subscriptions for a user?

I am integrating my site with PayPal and PayPal IPN for recurring subscription payments. Signing up works well,开发者_JAVA技巧 and I'm all good there.

However, I am trying to understand unsubscribing, and I have a big question.

My site offers different plans with different prices and features. I want to be able to change a user's plan when they decide to upgrade or downgrade. I also want to be able to let a user easily cancel their subscription.

My questions:

1. How do I allow a subscription to be changed?

2. Is a subscription change a cancel and then a subscribe?

3. Can I make the cancel seamless, where they don't have to go through paypal? How do I do this? (I have cancel buttons for each of my services, but I would prefer to have cancel be seamless to the user, just in my site).

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You can decrease the profile through UpdateRecurringPaymentsProfile. Keep in mind though, that there's a maximum increase of 20% over 180 days.
In short, if you want to decrease the profile, simply call UpdateRecurringPaymentsProfile and adjust the amount to be billed.
If you want to increase the profile, check whether it exceeds 20% of the original amount. If it does, cancel the existing profile and re-initiate the profile creation process (SetEC, GetEC, (DoEC), CreateRP) to create a new one.