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to transfer (trains); to change (bus, train)
to change (to another ideology, party, company, etc.); to switch (to a different system, method, etc.); to move on to (e.g. a new love interest)
次の駅で別の電車に乗り換えます。
I transfer trains.
彼は与党から野党に乗り換えた。
He switched from the ruling party to the opposition.
ここで乗り換えてください。
Please transfer here.