How to update Tree Name, Version in Project Accounting Business Function?

Summary:

Please suggest how to update the tree information for Project BUs?

Content (required):

We completed the setup Project Accounting Business Function for our Project BUs. Later, business decided to make use of Org trees and created the same. However, we are unable to update this setup anymore with the new tree information as the field is appearing to be greyed out.

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

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