clean up one's act

clean up one's act {infml} (to improve one's behavior; to stop doing things that other people do not approve of and start to behave in a more acceptable / suitable /sensible way; to stop doing things that are considered unacceptable) — исправиться, взяться за ум

Example 1: The more you nag her about her dangerous, self-destructive habits, the lower her opinion of herself will sink and the more she will indulge them. She will not clean up her act until she wants to do it for her own sake.

Example 2: He used to drink a lot, but he seems to have cleaned up his act. (CDAmIdi)

Example 3: A user of narcotics might be told to "clean up his act" by his parents.

Example 4:

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see also
[браться за ум]
[act your age]
[shape up or ship out]
mend one's ways
reform
a reformed character (someone who has changed and become a much better person)

Example 1: He was in trouble with the police a lot when he was younger, but now he's a reformed character. (CALD)