In order to delete a Production Order you must have the permission to do so. If you do not have the permission required you will not be able to perform this function.
Learn More: Production Overview
An Administrator or user provided with permission has the authority to delete a Production order by using the following method:
Open the Production Order to be deleted
Click on the “Manage PO” button at the top of the screen. This opens a drop-down list. Click on "Delete"
Prior to completing the deletion process, you will be asked to confirm the deletion.