Our basic process flow:
Our app creates an order, adds items, then pushes in Payment app with the order#, then once Payment complete it returns and handles the rest (ticket printing etc).
Currently, if a customer is indecisive and the employee backs out to add an item, then returns to payment, this counts as a new order. As a result, we have a lot of open/abandoned orders.
I can imagine going down one of two routes... either our app recognises when an order is abandoned (Currently struggling with this as there seems to be no special Intent), or we have something run at the end of day to clear up all open orders.