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to succeed; to relieve; to replace
to take the place of; to substitute for; to take over for; to represent; to hand over (telephone)
to be exchanged; to change (places with); to switch
季節が換ると空気も変わる。
When the season changes, so does the air.
住所が換ったら届けを出してください。
Please file a notice when your address changes.
話題が急に換ったのでみんな驚いた。
Everyone was surprised when the topic suddenly changed.