How to write multiple authors as (Smith et al., 2015)

Hi,

In endnote when you initially reference a paper it shows all authors then the next time you reference the same paper it has one author et al.

I do not want to have all authors written in my in text reference. I just want (one author et al., year) even for the first time the paper is referenced. How can I tell endnote to do this?

Many Thanks,

Sarah.