How to update level name after renaming Unit & Service

Hi everyone!

As the title states, I renamed several Units & Services in my OPM design file, the pipeline names changed accordingly, but the names of  levels which pipe elements reside in did not.

Is there a way to update them automatically?

Also I noticed that creating and editing named expressions are required in almost any OPM customization, can you provide some detailed document on that?

Thank you!