CHANGER is an innovative industrial-grade head blending technology that achieves high-fidelity head blending effects through chroma key technology, especially suitable for fields such as visual effects (VFX), digital character creation, and virtual avatars. This technology separates background integration from foreground blending, utilizes chroma key to generate a flawless background, and incorporates head shape and long hair enhancement (H^2 enhancement) along with the foreground predictive attention transformer (FPAT) module to improve its generalizability to diverse real-world scenarios. The main advantages of CHANGER include high fidelity, industrial-grade results, and extensive applicability to real-world cases.