RURL across apps

Hello, I feel like this is very simple and I think I may have even accomplished it before but I am drawing a blank. 

I am trying to let users add line items from one app to a parent record on anther app. I created the relationship and made sure to add the "Add Line Item" button and the report link. But when they add a line item(cross app child table) they are not returned back to the parent table once they press save, the record just saves and they are left on that record in the child table. 
Is there a way to save the child record and return back to the parent record?

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Amanda Torrisi
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