Adding "," and "&" in citations

Good day

I am currently using a harvard style citation, specifically for the journal animal conservation.

They journal requests that you in-text citation be author1, author2 & author 3, 2000. Unfortunately it is showing as author1, author2, author 3, 2000. I have gone to Edit- Output style- Edit style-Author list and changed the between and before last columns but with no success.

Is appreciate any advice on this

Thanks

Can you attach your modified output style to a reply to this message?  – You should be able to make the changes - but then save as to a new name and ensure that the newly named style is used in your word processor, not in Endnote.