NR 1.1.2, transpose: obscure sentence

[Federico Bruni]

I'm translating the Notation Reference and I found a sentence that I 
can't understand (I've never used \transpose).

NR 1.1.2
Transpose, Known issues and warnings

"The relative conversion will not affect \transpose, \chordmode or 
\relative sections in its argument. To use relative mode within 
transposed music, an additional \relative must be placed inside \transpose."

The second sentence is clear (it has been explained before). The first 
sentence not much to me. Can you make an example?

Thanks,
Federico