Concatenate single instance of duplicates

I don't know who this could be done as I don't know if it's possible. I have list of names in S13 and T13, last name and first name. This list is based on duplicates, so a name might pop-up 5 times. The problem is that it also contains duplicates of the same last name but the first name is different.
So, is there a way concatenate the last and first name, in such a way that will display only a single instance of duplicated name?
Hope I was clear enough.

S13 T13
John Fred
Taia Alice
Taia Alfred
John Fred
Taia Alice

And the result will be something like this:
John Fred
Taia Alice
Taia Alfred

Thanks for your time

yes but how do I use that as an automated sollution? The columns with names are actually a links to .txt files. So when i refresh the connections, the names should be sorted automatically and placed in a new column. Sorry about the concatenate, it wasn't really needed.