A fresh start; a complete change of attitude or outlook—turning over a new leaf and beginning anew.
転職して心機一転、新しい仕事にチャレンジするつもりだ。
I'm changing jobs and plan to take on new challenges with a fresh start.
引っ越しを機に心機一転、部屋を片付け生活習慣を整えた。
Taking the move as an opportunity for a fresh start, I tidied my room and organized my daily routine.
留学から帰国して心機一転、勉強に集中することにした。
After returning from studying abroad I decided to turn over a new leaf and focus on my studies.