# 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 columns attribute and change name 'A' & 'B'
df.columns = ['NewA', 'NewB', 'C']

# print the result
print(df)