1To change, alter, or revise something—such as a rule, plan, method, or way of thinking—into a different or updated form.
会社は来月から就業規則を改める。
The company will revise its work regulations starting next month.
彼は考え方を改めて、もっと柔軟に対応するようになった。
He changed his way of thinking and became more flexible in how he responds.
このアプリは来週、デザインを大幅に改める予定だ。
This app is scheduled to significantly revamp its design next week.
文章の誤りに気づき、すぐに表現を改めた。
I noticed a mistake in the writing and immediately revised the wording.
2To reform or correct oneself—fixing a bad habit or attitude and making it better.
遅刻癖を改めるために、毎晩早く寝るようにした。
To break my habit of being late, I started going to bed early every night.
彼は反省して態度を改め、周りから信頼されるようになった。
He reflected on himself, mended his attitude, and gained the trust of those around him.
一度失敗したことを教訓にして、やり方を改めるべきだ。
You should learn from a past failure and improve the way you do things.
3To carefully examine or check something, such as documents, identity, or belongings.
警備員が入場者の手荷物を改めた。
The security guard inspected the visitors' bags.
税関で荷物の中身を改められた。
My luggage's contents were inspected at customs.
係員がチケットを改めてから会場に入れてくれた。
The staff checked our tickets before letting us into the venue.
4To do something properly or formally; often used as 改めて to mean doing something again, at a more suitable time, in a proper manner.
本日は取り急ぎご連絡まで。詳細は改めてご説明いたします。
This is just a quick message for now; I will explain the details properly at a later time.
契約書の内容を改めて確認してからサインしてください。
Please formally review the contract's contents once more before signing.
引っ越しの挨拶は、後日改めて伺います。
I will come again another day to properly greet you about the move.