How to update a variable inside a Multi‑Row Set via Flow Designer

[FabiW]

Dear all,

I’m facing a small challenge with a catalog item that uses a Multi‑Row Set variable.
Within my Flow (Flow Designer), I need to update or add a value (specifically the deviceName) inside one of the rows of this Multi‑Row Set.

So far, I can read the Multi‑Row Set data, but I haven’t found a way to update a single field inside the Multi‑Row Set and write it back to the request item.

Does anyone know the correct approach to modify a variable inside a Multi‑Row Set via Flow Designer?
Is there a supported method to update a specific row or field, or do I need to rebuild the entire JSON structure and write it back?

Any guidance or examples would be greatly appreciated.

Thank you!