I make a purcahse order for a product with quantiy=10 price=$ 2. order total=$ 20. I have received quantity 2 and created an invoice to this purcahse order. I have edited price of the product to $ 3. Now invoice toatal=$ 30. I have paid this $ 30 using a bank journal. But the purchase order status not changed to done. It's still in "purcahse order" status. Can any one  please suggest me, how this po become done state?