title: Sitecore: how to move a Field to one of my Base Templates without losing data
body: <p>Let's say that my "Toyota" template has "Car" as its Base Template.</p>
  
  <p>I want to move the field "Windshield" from "Toyota" to "Car", but I don't want all instances of Toyota to have it reset to null.</p>
  
  <p>Is there a safe way to go about doing this?</p>