Not able to update/edit functional area catalogue

Summary:

We had defined the functional area catalogue with the option as " Assign items to leaf level categories only" now we want to change and enable the option " Allow multiple item category assignments". But the update button is greyed out. How can we update/edit the current configuration for this?

Content (required):

Version (include the version you are using, if applicable):

22B

Code Snippet (add any code snippets that support your topic, if applicable):

NA