Update Order Once a New Delivered Record Is Added

[MajikCroaks]

I have an order list and a delivered list.  The delivered list has an "owner" column that is the key to the order list.

What I am trying to do is, whenever a delivered record is created, I would like to update the stock column in the order list by deducting the quantity that is delivered.

I have been trying with reference action but cannot make it work.  

[shahappsheet]

It can be done using action. when the item (quantity) is delivered, it can be updated the stock in many ways based on your requirement using action. That action can be called from the following behaviour event of a form. If more than one actions are required, then create a group action and call that group action.

[SkrOYC]

I think that if you are using a Virtual Column with the qty it should update automatically everytime a new child is added.

Can you share your expression and column config for the [Stock] column?