There have been many reforms in history, and your question is a little unclear, but there are three famous ones:

Shang Yang's political reform-the symbol of China's history from slave society to feudal society.

The Reform Movement of 1898 —— China tried to take the capitalist road.

Reform and Opening-up —— China entered the socialist society from the planned economy.

The initial transformation into a market economy ended China's appearance since the Ming Dynasty.

The history of closed doors