SAP Message MM326 - There are still open purchase order items or scheduling agreements

Diagnosis
You wanted to change the valuation class or the profit center. However,open purchase order items orscheduling agreements stillexist for the material. This can result in inconsistencies if goodsreceipts and invoice receipts are posted for the corresponding purchaseorder items.
Note
This message or the setting in Customizing for this message (see below)is also relevant if thematerial type of a materialis changed and if the new material type requires another valuation classto be assigned.

Procedure
Close these purchase order items and flag them for deletion.

Procedure for System Administration
In Customizing for the Material Master, you can define that thismessage appears only as a warning. You do this inDefine Attributes of System Messages.However, first ensure organizationally that further processing of thepurchase orders cannot result in inconsistencies.
Due to the importance of this message, it still appears as a warningeven if you assign the message type No message to it.