Not just for NFPs, but for anyone.
Are your Fi values more or less constant throughout your life? Have you ever ended up rejecting one of your Fi values that you had formerly held? Seems more common that they gradually evolve and refine rather than change completely. However, if you've ever gone totally from one value to another, maybe say from believing one thing to be important to believing the opposite to be important instead, describe the situation and the process, to the extent possible.