Price and inventory of "Approval Completed" products cannot be changed using [Product Modification API].
Please refer to below list and use the corresponding API to make your changes.
- originalPrice (base price for discount rate): [API to change product item level discount rate's base price]
- salePrice (selling price): [API to change product item level price]
- maximumBuyCount (quantity available for sales-inventory): [API to change product item level quantity]