Update one or more fields of a specific folder link.

    **Supported operations:**
    - Update folder assignment
    
    **Restrictions:**
    - You cannot change the phone number to a different number
    - You cannot update person data through this API (use the person API directly)
    - The phone_number field is optional for PATCH operations
    
    **Examples:**
    
    Update folder assignment:
    ```json
    {
      "folder": "new_folder_id"
    }
    ```
    
    Note: Person data updates are not supported via PATCH operations.
    Use the person API directly to update person information.