I am using the Express Checkout API to accept payments for my online store. The payment flow is as follows:
1) User adds Item to Cart
2) User proceeds to PayPal
3) User enters or selects existing shipping address, confirms, and is redirected to order confirmation step
4) Order Details such as Shipping Address are retrieved from PayPal using GetExpressCheckoutDetails.
5) On the order confirmation step (prior to DoExpressCheckoutPayment), user has the option to change the shipping address returned by PayPal. If user changes the shipping address, I need to recalculate the shipping cost to this new address, and submit the new shipping cost, as well as the new address back to PayPal
6) I am attempting to do this as part of the DoExpressCheckoutPayment payment call, using PAYMENTREQUEST_0_SHIPTONAME etc, but the shipping address within the transaction details does not change. (Likely because these are deprecated) Instead, the address chosen or entered on PayPal remains.
How can I submit a new shipping address to PayPal without having the user re-enter the transaction funnel from the beginning?