Extract variable information from JSON

Dear KNIME community,

I have a problem, for which I currently find no solution.

We retrieve updates on records from a database provider and I want to extract the changed information only.

Unfortunately with the provided API call one will always receive the complete record, in this case on a drug, instead of only the changes.

The changes are noted in a section called changedField.

To get only the changes I would need to extract the Filed Names, of the fields where changes happened, and then retrieve the information from these fields. As far as I get it some sort of variable XPATH/JSONPATH would be needed.

I have never heard of anything like this.

Any idea from you how this could be handled?