see turn over a new leaf.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
Examples from the Web for new leaf
Over the exquisite forest of new-leaf trees the stars came out at length, and the guardians began to observe him.Fairfax and His Pride|Marie Van Vorst