Hello kapilkumar;
What is your question? What problem have you faced?
With a S7-400, there is no requirement for reset after changing batteries, they should be changed while the system is functionning...
Chapter 7.1 of this manual: S7-400 Hardware and Installation, will guide you in the details of changing the batteries. http://support.automation.siemens.com/WW/view/en/1117849
Hope this helps,
Daniel Chartier