Change managed account password?

I have a managed account on my MacBook Pro that I use for my kids. I waned to go in to change their password but can't seem to figure out how to do so. If I log in as an administrator, I can't select their account and if I log in under their account and allow myself into account preferences, the "change password" button is grayed out. I assume I'm doing something simple wrong, but can't figure it out. FYI, there are parental controls on that particular account. Anyone able to give me a little nudge in the right direction?

Thank you!