To Be Renewed
To Be Altered, To Be Revised, To Be Formal
intransitive verb, godan verb
This word consists of kanji with hiragana attached. Because the hiragana ends with an う sound, you know this word is a verb.
The kanji itself means renew so the verb vocab version is to be renewed. Like most verbs ending in まる, this is an intransitive verb, meaning it doesn't take a direct object. Something renews or gets renewed, or something changes. See? No direct object.
Although it's not often translated as "renew," 改まる implies a kind of renewal in the changes it's used to describe — whether it's the revision of regulations or the old year changing over to a new one. It can also be used for personal improvements, or describe a shift to a more formal demeanor in social situations.
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You might remember this reading from the transitive verb 改める, but here's a mnemonic just in case:
To be renewed means to be changed into something 新た (あらた). Out with the old, in with the 新た, right? Picture yourself in a situation where there's been a lot of change. Try to remember how it feels when everything is 新た. Are you nervous, excited, or do you usually move on without noticing?
まさか日本の年号がワニカニに改まる日が来るなんて！
I never thought I'd see the day that the Japanese era name was changed to WaniKani.
そう改まるなよ。うちの社長は、とても気さくなんだから。
Don’t be so formal! The president of our company is very friendly.
その山の上で空を見上げると、心が改まるような気持ちになりました。
When I looked up at the sky from the top of that mountain, I felt my heart become solemn.
アイツの悪いクセがすぐに改まるとは思えないよ。
I don't see his bad habits changing anytime soon.