This call is used by the seller to issue a partial refund to the buyer. This call can only be invoked after the buyer accepts the partial refund offer. This call can only be used if the payment method for the order was PayPal.
The seller enters the amount of the partial refund that is being offered to the buyer. This amount is in the currency used by the listing site. This amount must be identical to the amount offered through the offerPartialRefund call.