Hello
Could you please explain "then i create Child order with Co07 then how i can GR from Parent order ?"
CO07 is generally used for the rework (without material code). We do not perform any GRN activity (MB31) against the rework order.
Generally the rework process is
Rework notified against the order (Parent order)
Rework order created with CO07 (without material) with Settlement rule maintained as Parent order.
Machine hour booked and Material consumed against the rework order.
NO MB31 as the rework order is without material code.
While settling the rework order the cost will flow to the parent order.
If you already did the GRN against the Parent order than no need to the extra GRN. Just do the rework activity and settle the extra cost to the parent order.
Hope this may help
Regards
SS