What is a way for people to approve changes in laws by vote

Citizens initiative

Explanation:

Citizens initiative is an initiative in which the citizen who are registered as voters of the state can formulate and sign a petition for the purpose of the enactment of a law or for taking a law down.

This is a way for letting the government know of the citizens who are also the ones who voted the government, can get their voice across and can possibly bring the required change in the law.