using VA02 tcode sales order deletion

Problem is: user getting error "you cannot select assembly order(production order number) for deletion" while trying to delete item from sales order using transaction code VA02.

other info: corresponding production order status is

"TECO PRT CNF DLV PRC BASC BCRQ GMPS"

could anybody can tell me what is the reason for this? and how one can delete the same.

Appreciate your quick resolution.

Thanks,

Aritra

Message was edited by: Aritra Samanta