改換

to change (sth) / to alter (sth) / to change over (to sth else)

to change / to alter / to transform / to correct

to exchange / to change (clothes etc) / to substitute / to switch / to convert (currency)

to improve one's family's social status by moving up in the world / to switch one's allegiance to a new patron

see 改換門庭|改换门庭[gai3 huan4 men2 ting2]