This paper presents the view that tropes can change, and so are not individuated by their determinate qualitative characters. On the view I have in mind, a trope is at any given time fully determinate, but can change qualitatively within the bounds set by a determinable essence. A charge trope, for example, must at any time have some exact intensity, but can survive changes in intensity. My argument, roughly, is this: Objects can change, and tropes are the parts of objects that change (in a special sense of ‘part’), so tropes can change too. After some preliminaries, I present the argument carefully and discuss the operant notions. I then discuss each premise in turn. I respond to the charge that the view isn't realist, and to objections based on identity‐conditions for tropes. I describe both substratum‐ and bundle‐theoretic versions of the view, and finally, show what the view buys us.