Updating Action Code in Order Line item through WF/Script in Modify Order

Hi Team,

I have requirement to update action Code(modify the products) in Order Line item through WF/Script in Modify Order just like the way I hit the Customize button and change the product and click the done button and the old products show action code Delete and the new ones show Add. How to achieve this? Do I need to call Done signal?

I am actually confused with, there are few old products which after I modify, show - in action code and few show Delete in action code. So I want to build a logic so that I could put - for the  products for which configurator will put - and Delete for the others.