What is the API for splitting po requisition lines quantity ?

I want to split the requisition  into two lines，the original quantity is 2,then divide into two new rows which quantity are all 1.I find this documents：

BUT I need API to split requisition line quantity.So I use procedure po_requisition_update_pub.update_requisition_line to modity the old quantity to 1,and add new quantity 1,then I split one line to two lines.Am I doing the right ？