Creating a child record from a button on the parent form and automatically return back to the parent form after the child has been saved.

Yes, that is what I want. Once the root cause record is created I want the user to only to have access to edit that record and not able to keep "adding" new records.

What is currently happening is once the user creates a record for root cause the "add" button is not changing to edit mode and allows the user to keep adding new records.