Hi Kumar,
If you want to update server database, then you need to use server side database in connection string like this
SqlConnection conn = new SqlConnection("user Id=rk.prabakar; Password=rk.prabakar; server=192.168.1.XX\SQL2008R2; Database=TestDatabase;");
Replace the server name with your actual server name that you intend to update.
Server SQL instance name may be like
192.XX.XX.XXX/SQLServer
(comes with ip address and sql instance name)
Change userid and password with your username and password that is used to connect remote database
Hope this helps you a bit.
Regards,
RK