Ichidan verb, Transitive verb
to transfer (trains); to change (bus, train)
東京駅で列車を乗り換えなさい。Change trains at Tokyo Station. 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)
Also written 乗り替える【のりかえる】