To turn over a new leaf means to begin again, fresh.
To start behaving in a better way.
Make a change in one’s conduct or attitude.
1. Why don’t you turn over a new leaf and show everyone that you can behave appropriately.
2. It’s time to turn over a new leaf and stop eating all this junk food.
3. Surprisingly, he’s turned over a new leaf and quit smoking!
4. This spring, I plan to turn over a new leaf and start to workout and eat healthy.
amend, change one’s ways, clean up, clean up one’s act, improve, rebuild, rehabilitate, remake, renovate, reorganise, repair, resolve, restore, revise, revolutionise, shape up, standardise, swear off, transform