"There are a few ways, all of which would work to some degree or another. It's up to you to choose which course of action is best of course.

The first solution is the simplest. You find a method of destroying Queen Chrysalis and freeing Broken Scale. There are a multitude of ways to do this, but considering you're a paladin, I doubt that's what you're looking for. The easiest would be draining her of magic, since changelings are innately magical beings, and can't exist without it.

The next, and much harder possibility, is finding the ingredients to an elixir that is capable of purging the changeling mutation from her body, and splitting Chrysalis and Broken Scale into two separate people. There exist no spells to do this, and I would be breaking my own rules for a reason that isn't quite good enough if I were to create one to give to you.

The last, and hardest, is the former, followed by finding a way to change the base nature of Chrysalis so that she doesn't have to exist as a parasite. If you change the nature of the queen, the other changelings will follow.

So, paladin, how far out of the way are you and your group willing to go to save and heal a ruined race?"