Answer:
Reflection.
Step-by-step explanation:
The prompt is asking you to "write an essay about a change that has occurred in your life", essentially asking you to reflect on what has occurred in your life, and what exactly it changed.
For example, a person may have been in a car accident before. If their essay is about the car accident, it will be something along the lines of how the car accident may have changed their perspectives on cars in general, or even other human beings and their behaviors, which may have led to and resulted in the car accident occuring.