do you have a style that matches everything else you need? Is this in the citation (in the text) or in the bibliography?
It is easy to adjust if you have one that matches the rest of your criteria. (albeit, it is usual to show 3 authors or less and not 2 or less). Depending on whether it is is citation or bibliography or both, you adjust the settings in the output style you have chosen. Two images are attached.
You get to these settings in Endnote,
Edit menu, Output Styles
Edit “the style you are using”
then go to the Author Lists for either Citations (those that will be in the text) or Bibliography (how it will be listed in the reference list) or both and set the highlighted numbers to 3 or more list 1.
(added in edit) Oh yeah, forgot to say, – save as to a new name, and then in the document you are using, change to use this newly named style. – you may have to choose “select another style” from the Endnote ribbon or toolbar to see the newly created style.