summarizing data without a pivot table?

I am trying to summarize data as if I where to run a pivot table on it but I need to make it all automated so that my field guys can handle it. In other words no pivot tables! What I am trying to do is summarize a list of names from one tab to make it to where each name only appears once.

So if I have:
John
Jason
Ed
Mike
Mike
Mike
Jason
Jason
John
Ed
Mike

I would just get
John
Jason
Ed
Mike

I am sure it would be an index function of some sort but not sure how to get it to work. Thank you in advance for your help.

JZ