# 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.values and change 'A' & 'B'
# A is at index 0 (first col), and B is at 1
df.columns.values[0] = 'NewA'
df.columns.values[1] = 'NewB'
# print the result
print(df)