/refund

Request body:

Field	Type	Required	Format / constraints
documentID	integer (int64)	No	Internal document id
documentExtID	string	No	External document id
docTime	string	No	yyyy-MM-dd HH:mm:ss
docNumber	string	No	External document number
employeeName	string	No	Cashier name
employeeFirstName	string	No	Used when employeeName is empty
employeeLastName	string	No	Used when employeeName is empty
items	array of item objects	Yes	Must be non-empty
payments	object	No	Payment split object
extraPayments	array of extra payment objects	No	Additional payment entries
parentDocID	string	No	Original sale reference
parentDocNum	string	No	Original sale number

Success response: same field set and value rules as /sale.