i have a query on symhelp.

symhelp run online or as offline?

for the offline clientwhich tool i can used for the scan?

Is there any setting where i can change it for scan with symehlp?

You need to internet connection when run symhelp tool

About the new SymHelp tool for SEP 12.1RU2

http://www.symantec.com/connect/articles/about-new-symhelp-tool-sep-121ru2

For what purpose i require the internet connection.

What tool is for offline scan?

See mithun articles

NOTE: It is recommended to have an Internet connection when using SymHelp and Symantec Power Eraser. This would assist in downloading the Latest Version of SymHelp and Latest Power Eraser Definitions when running Symantec Power Eraser. Incase, there is no Interent connection, Power Eraser would use the default definitions which are available with the SymHelp Tool.

http://www.symantec.com/connect/articles/symantec-power-eraser-using-symantec-help-symhelp-tool

Any other tool in symantec which run offline?

You can use SERT tool

How To Use the Symantec Endpoint Recovery Tool with the Latest Virus Definitions

you can run the Symhelp offline, however to check the files againg Symantec reputation  server the tool need internet connectivtiy.

To complete a scan that was run without connectivity to the Symantec Reputation database run SymHelp on a system with access to the Internet and from the Home page, in the menu at the top, choose File > Open Report and open the saved .sdbz.  Select the 'Threat Analysis' tab and then click the 'Complete Report' button.

http://www.symantec.com/business/support/index?page=content&id=TECH215519

Symhelp will be runned without internet connectivity

You can run a scan without connectivity to the Symantec Reputation database but not all of the features available in the Threat Analysis Scan will be available. 

How to run the Threat Analysis Scan in Symantec Help (SymHelp)

Symhelp needs internet access if you want the reputation database

Otherwise go with SERT or Norton power eraser

What is these tool SERT or Norton power eraser?

See this mithun articles

The Symantec Endpoint Recovery Tool (SERT) is a bootable CD that can scan and remove malware from an infected computer. SERT is useful in situations where computers are too heavily infected for the Symantec Endpoint Protection client installed upon them to clean effectively. It is also necessary against specific threats which have the ability to completely hide from Windows, or that have techniques that manipulate Windows into protecting the malicious process against Symantec Endpoint Protection's scanning and remediation components

Symantec Endpoint Recovery Tool (SERT)

http://www.symantec.com/connect/articles/symantec-endpoint-recovery-tool-sert

SERT tool is avaialble in file connect

https://symantec.flexnetoperations.com/control/symc/registeranonymouslicensetoken

How to make the Symantec Endpoint Recovery Tool boot from a USB memory stick

How To Use the Symantec Endpoint Recovery Tool with the Latest Virus Definitions

Symantec Endpoint Recovery Tool (SERT) requires a PIN to run

To create a Case OR call Symantec Technical Support, check below:

How to create a new case in MySupport

http://www.symantec.com/docs/TECH58873

Regional Support Telephone Numbers:

United States: https://support.broadcom.com (407-357-7600 from outside the United States)
Australia: 1300 365510 (+61 2 8220 7111 from outside Australia)
United Kingdom: +44 (0) 870 606 6000
Additional contact numbers: http://www.symantec.com/business/support/contact_techsupp_static.jsp