I have a spreadsheet with three columns: year, name1, name2. Each entry represents a pair. I've noticed that there are duplicates in the data that Excel does not detect, namely:
So the only pair in year 1986 is ABW-AIA. However, in the data I've got two entries: ABW-AIA and AIA-ABW. I would like to remove either ABW-AIA or AIA-ABW, so I am only left with one entry. I would like to repeat the same process with many other pairs. How can I do this?
I'll greatly appreciate any help!

