The Heart Changer is a finishing move used by Kwazii when using his Humphead Parrotfish Charm from his Ocean Pearl Bracelet.
It's similar to Amu Hinamori's Open Heart ability and like the Open Heart, it can cleanse people's hearts and it can change people's crooked hearts by filling or purifying them with love and care or confidence if the person is feeling hopeless. The Heart Changer can also fix broken hearts. It supposedly uses the power of the Humphead Parrotfish charm from Kwazii's ocean pearl bracelet, since he is the only one who has the ability to use it.
The phrase goes by "Time to fill that heart with love, matey- Change of Heart!", but only in a battle with a person who's being possessed by an evil spirit in the person's body or in an amulet.