To update a payment, you use payments resource. They are a reference of the actual payment that happens at the payment gateway.
Payments handle customers' actual payments of previously defined order.
|initial-payment||use when a customer is purchasing the order in the checkout|
|initial-free-transaction||use when the customer is not charged, for example, if he has a trial period applied, or got a 100% coupon code|
|recurring-payment||use when the customer is charging for renewal payment|