On May 22, 2:29 pm, Susanne wrote:
In column A I have the names of the participants and in column B I have the
names of their room mate. Meaning that everybody are mentioned in both
columns of course. Now I need to check that if John is Kenns room mate then
Kenn is also Johns room mate.

Could anyone please help me.

Thanks,
Susanne

In column C (C2)
=IF(INDEX($A$2:$A$100,MATCH(B2,$A$2:$A$100,0))=B2, "Match","No match")

You can then use filter on C or simply spot inconsistencies.

HTH
Kostis Vezerides