I appreciate the quick responses!
Unfortunately, the plugin repository doesn’t have any plugins that are up-to-date with WP 4.3 and in 4.3 the entire registration/password concept has changed. So I need to change it myself, manually.
I don’t want to change the functionality of the user having to sign in to change her own password, I just want to customize the instructions. So I need to know where in the code to do that myself.
Thanks!