change over vs turn around

change over

verb
  • to convert to, to make a transition from one system to another 

turn around

verb
  • To change drastically in a fundamental way, often for the better; to change to the opposite (opinion or position). 

  • To consider from a different viewpoint. 

  • (often with a unit of time) To produce; to output; to generate. 

  • To suddenly change or reverse one's opinion, point of view, stated position, behaviour, etc. 

  • To reverse an expected outcome (of a game, etc.), usually from a losing outcome to a winning one; to return (a business, department, etc.) to effectiveness, profitability, etc. 

  • To physically rotate (usually around a vertical axis) for a half turn (180 degrees), a whole turn (360 degrees), or an indefinite amount. 

  • To convert (an agent) to work for one's own side. 

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