Now you are getting into the nitty gritty of EndNote’s power.
In endnote preferences (edit preferences) you can modify a reference type (which kind of reference do you use for the WHO report?) see https://support.clarivate.com/Endnote/s/article/EndNote-Adding-and-Changing-Reference-Types?language=en_US
And then, this page has a video (but it really focuses on constructing a brand new output style which isn’t necessary) – you really want the PDF attachments for Window or Mac to edit the output style (they are at the bottom under the video screen).