change vs vary

change

verb
  • To become something different. 

  • To replace one's clothing. 

  • To replace the clothing of (the one wearing it). 

  • To change hand while riding (a horse). 

  • To transfer to another vehicle (train, bus, etc.) 

  • To make something into something else. 

  • To replace. 

noun
  • The process of becoming different. 

  • A change-up pitch. 

  • An amount of cash, usually in the form of coins, but sometimes inclusive of paper money. 

  • Small denominations of money given in exchange for a larger denomination. 

  • Balance of money returned from the sum paid after deducting the price of a purchase. 

  • A transfer between vehicles. 

  • Any order in which a number of bells are struck, other than that of the diatonic scale. 

  • A replacement. 

vary

verb
  • To be or act different from the usual. 

  • To make of different kinds; to make different from one another; to diversity; to variegate. 

  • To embellish; to change fancifully; to present under new aspects, as of form, key, measure, etc. See variation. 

  • Not to remain constant: to change with time or a similar parameter. 

  • To institute a change in, from a current state; to modify. 

  • To change with time or a similar parameter. 

  • To display differences. 

How often have the words change and vary occurred in a corpus of books? (source: Google Ngram Viewer )