I have 2 form

1st is Purchase Order form which subform is Order_list that containd Material_Code, Order_Qty, Received Qty, Balance_To_Receive_Qty

2nd is Receive form which subform is Receive_List that contained Material_Code, Balance_To_Receive_Qty, Receive_Qty

Reveive_List.Material_Code and Receive_List.Balance_To_Receive_Qty I use lookup code from Order_List and Receive_Qty is field for user input.

My question is how to write code for partial receive

eg.  when sucess Receive form submission Receive_List.Receive_Qty have to updeted in PO_List.Received_Qty(this field has to be accumulated from last time i created Receive form for this Purchase Order) and recalculate PO_List.Balance_To_Receive_Qty