hand on vs swap out

hand on

verb
  • To transfer (something) to someone else, especially as a replacement for oneself (such as an official office or duty); to transfer something that was originally given to oneself from someone else. 

swap out

verb
  • To exchange (something or someone) for an unused (or less-used) equivalent. 

  • To exchange (something) for (something else). (usually followed by with or for) 

  • To transfer (memory contents) into a swap file. 

noun
  • Anything that is swapped out for another; an exchange. 

  • A pre-prepared food item used in place of an unfinished food item in order to cut down the overall preparation time during filming. 

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