Unable to update quantity in purchase requisition referred in internal sales order
                    
Created a Purchase requisition (iprocurement) and an internal sales order booked.But for the same requisition unable to update quantity by change function.( R 12.1).Following steps also made but unable to update quantity in the requisition.System gives an message"Changes areot allowed".Purchasing > Setup > Tolerances and Routings > Requester Change Order                 
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