How to define index column name using df.to_csv

[SriRajesh]

Hi,
I have dataframe, and I want to write to csv. But when write to csv, the first column name disaaper (which is Index)

Before write,
Index c1 c2
A 2 5
B 5 9

I use below command,

1	summary_table.to_csv('outsummary2.csv',index=True,header=True)

when I open csv file, data look like:

1 2 3

c1 c2 A      2  5 B      5  9

how can rename the index column name? to look like my data:

1 2 3

Names c1 c2 A      2  5 B      5  9