dupe of https://mangapark.io/title/372009-en-i-can-do-it

Assistant manager Cho Daechan who worked as a office worker for ten years died in vain from being overworked at a young age, because he could not endure the abuse of power of his evil boss. He thought it was all over... He opened his eyes again as a 18 years old high school student. A miraculous opportunity that will never happen again. “In this life, I will grit my teeth and live my life! I will clear up my life of being trampled on and succeed as if I am showing off. You don't think I can do it? No, I can do it!”