换代

换代	huàn dài	to transition to a new dynasty or regime / to replace an older product with an upgraded, new-generation one
换	huàn	to exchange / to change (clothes etc) / to substitute / to switch / to convert (currency)
代	dài	to be a substitute for; to act on behalf of; to replace; to substitute / generation; dynasty; age; period; (historical) era; (geological) eon