come back vs request

come back

verb
  • To retort. 

  • To return to one's possession, especially of memories. 

  • To return to a former state, usually a desirable one; to become fashionable once more. 

  • To return to a place. 

request

verb
  • To ask (somebody) to do something. 

  • To ask for (something). 

noun
  • A message sent over a network to a server. 

  • Act of requesting (with the adposition at in the presence of possessives, and on in their absence). 

  • Condition of being sought after. 

  • A formal message requesting something. 

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