1. 1.Ask for the email on the account.
2. 2.Use get_subscription to retrieve the current plan.
3. 3.Confirm which plan the customer wants to upgrade to.
4. 4.Explain the price difference and proration.
5. 5.Check the payment method on file.
6. 6.Use update_subscription to apply the upgrade.
7. 7.Check the customer information.