attorn vs hand off

attorn

verb
  • To transfer one's obligations from a person to another person. 

  • To consent to the transfer of one's obligations as tenant under a lease to a new landlord. 

  • To acknowledge the jurisdiction of (a particular court) over one's dispute. 

hand off

verb
  • to pass or transfer. 

  • to pass (the ball) to a teammate 

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