I think there is some misunderstanding there, natural selection does act on an individual and can be determined by its genes (assuming there is genetic variance underlying the variance in trait). Those with more favourable genes will have more favourable phenotypes and thus be more likely to survive/reproduce. However, (genetic) evolution does not occur within an individual, evolution occurs at the population level as the frequencies of existing and new mutations changes over time or space.
Following from your example: Two morphs of a species exist, brown and white (like the classic peppered moth), which is genetically determined, and one has a selective advantage - let's say brown. Thus all individuals of the brown morph are more likely to survive and reproduce. Over time the genes causing the brown phenotype will increase in frequency in the population and frequency of brown (white) moths will have increased (decreased).
I suspect it would be helpful if you included more of the text preceding the statement.
Edit: having seen @fileunderwaters answer, which arrived seconds before I posted mine, I see that I was right, more of the text was useful :)
So going back to the moths, an individual moth would not be able to change it's trait in response to selection.