Hi there.
Good question.
Lets say you were going to an airport with one runway which only had an ILS approach on one end of the runway. And lets also say that the runway orientation was 09 - 27 and the ILS was on RW 27. If you got there and the wind, for example was 090/20 and the tailwind limit for your aircraft was 10 kts you would not be able to land on RW 27, therefore, you would fly an instrument approach on to RW 27 to your circling minima, then circle to land on RW 09 so that you landed with a head wind.
I hope that makes sense.