You can enable the Order Approval Feature in General Settings- Purchase Process Custimization. Order Approval is applied to Simple Purchases, Service Purchases and Advanced Purchases. Once an order is authorised, instead of going directly to the Stock Received or Invoice tab, the options Reject and Approve will appear. • Clicking Approve will continue to the next tab as usual to continue the purchase process. • Clicking Reject will convert the purchase order to a rejected purchase order. Rejected purchase orders are read-only, and payments cannot be applied.