when pick confirmed ,how to back order partial delivery line,if we donot want to ship all

hello ,

 when sales order picked released,we  can back order partial  move order lines, if we donot want to ship some of the order line.

but if  sales order pick confirmed,in  the standarded function ,we must back order the all deblivery no  if we donnot want to ship one of the order line .

Can only back order one  of the delivery lines if  we donot want to ship one order line when order have been picked confirm ,

Thanks .