# import necessary libraries
import pandas as pd

# create a sample df
df = pd.DataFrame({'A': [1, 2, 3],
                   'B': [4, 5, 6], 
                   'C': [7, 8, 9]})

# use rename() method and change col 'A' & 'B'
# use inplace=True to make changes to original df
df.rename(columns = {'A': 'NewA', 'B': 'NewB'}, 
            inplace = True)

# print the result
print(df)