Each processed order can be refunded using refunds API described here: Refunds API
Refund is basically payment resource related to specific order where sender and destination accounts are switched comparing to original payment created to collect money from the merchant’s customer (when merchant’s customer paid to merchant).
They can, similarly to payments, be processed by one of two flows:
Redirect flow
Embedded flow
The maximum amount of the refund is restricted by the value specified in the field “refundLimitPercentage“ provided in the request body when creating the order. By default (if not specified) it is 100% (meaning the same amount as the amount of the order).