Change Valuation Class

Step to Resolution ;

Scenario
My users wrongly created a material with valuation class 1003, the correct valuation class is 1000.

Now, i need to changes the valuation class from 1003 to 1000 by using MM02 (Accounting View). but it's could not change to 1000 because there is available stock for that material. I have transfer that material to other plant in order to change the valuation class. after i transfer that material to other plant i trying to change the valuation class but it's cannot work also....

i don't know why... i have check Open PO, Open reservation .... and so on but could not find cause of this problem

Solution
If open Purchase Order exist, then first flag the corresponding purchase order items for deletion.
If production orders exist set the status of the production orders to Deleted.