Humans have been changing their appearance for millennia.
Common methods are cutting or styling the hair. Different materials or cut to the clothes. Dying the skin — either temporary or more permanent.
Many changes are make in attempts to improve appearance — attract a mate. Others are to promote ease of movement. Some of the extreme towering wigs and wide skirts of the noble class did not stay in style for long. I know I would have a difficult time getting into a carriage or walking a narrow garden path in some of the highest fashions.
Humans are not the only creatures which change appearance. In addition to many examples of camouflage in the animal kingdom, some creatures undergo a radical change.