As per provided privileges from eZee Optimus back base on Outlet and User level system allow to approve or reject purchase Order.
1) Add purchase order from Purchase Order tab from the inventory section.
2) Recall that purchase order by clicking on that Purchase order.
3) Once you recall purchase order you can view “Cancel, Approve, Reject and Save” tab.
4) As per the selected button, you can view purchase order status refer below screenshot.