ATO FLAG on Sales Order line

Hi,

Our business wants few parts to be used as per back to back order functionality. Now since there are few open lines and deliveries for the parts so we can not check the Assemble to Order flag for the parts on item master.

I am thinking to run a test on dev instance where in I want to update ATO_FLAG on oe_order_lines_all via SQL and check if this option helps for the open lines. But when I am trying to update ATO_FLAG, I am getting errors like inavlid column, I learned that a ato_line_id gets assigned to a SO line as soon as the ATO part is selected on sales order so is there anyway to udpate ATO_FLAG directly on line.