Vary
Part of speech: verb
Definition: To change with time. Not to remain constant. Of a group, to display differences.
Example sentence: Crime is terribly revealing. Try and vary your methods as you will, your tastes, your habits, your attitude of mind, and your soul is revealed by your actions.
Alter
Part of speech: verb
Definition: To change the form or structure ofTo tailor clothes to make them fit
Example sentence: A small body of determined spirits fired by an unquenchable faith in their mission can alter the course of history.