import pandas as pd
values = {'dates': ['02-Sep-2019','13-Sep-2019','21-Sep-2019'],
'status': ['Opened','Opened','Closed']
}
df = pd.DataFrame(values, columns = ['dates','status'])
df['dates'] = pd.to_datetime(df['dates'], format='%d-%b-%Y')
print (df)
print (df.dtypes)