You can click on forgot password then enter user name, password will be sent on email which you have attached

https://www-secure.symantec.com/connect/articles/how-reset-symantec-endpoint-protection-manager-console-password-sep-121

How to create a new case in MySupport

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

OR 

Phone numbers to contact Tech Support:-

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

Resetting the administrator user name and password to admin for SEPM 12.1

http://www.symantec.com/business/support/index?page=content&id=HOWTO54992

Resetting the administrator password to admin (11.x)

http://www.symantec.com/business/support/index?page=content&id=HOWTO26949

nd check this as well

http://www.symantec.com/connect/articles/how-reset-symantec-endpoint-protection-manager-console-password-sep-121

Resetting a forgotten password

http://www.symantec.com/docs/HOWTO55059

Resetting the administrator user name and password to admin

http://www.symantec.com/docs/HOWTO54992

If all else fails, you can call suport and they will provide the resetpass.bat tool for 12.1

There are two way to reset the forgot.

First Process

To reset a forgotten password

1. On the management server computer, click Start > All Programs > Symantec Endpoint Protection Manager > Symantec Endpoint Protection Manager.

2. In the Logon screen, click Forgot your password?.

3. In the Forgot Password dialog box, type the user name for the account for which to reset the password.

   For domain administrators and limited administrators, type the domain name for the account. If you did not set up domains, leave the domain field blank.

4. Click Temporary Password.

   An email that contains a link to activate the temporary password is sent to the administrator.

   As a security precaution, the administrator must change the temporary password immediately after logging on.

Resetting a forgotten password

Second Process

You can use the resetpass.bat tool to reset the user name and password for the account. For resetpass.bat contact with tech support

Resetting the administrator user name and password to admin

Hope it Help.

Hi Mehra007,  

Please find the tool and steps in the link below.

https://www-secure.symantec.com/connect/downloads/how-reset-sepm-password-121x

hope it helps keep us updated.

Jeshrel@ ihave tried to reset the password but not work

Have you tried to set the password with forgot password as mention in attach article?

Hello,

after run reset.batch you should use defoult user name and password.

Username: admin

Password: admin

Hi Mehra,

Whats your SEPM version?

If the tool fails please run management server configuration wizard once and then unzip the resetpass.bat and place it in tools folder and run it with administrative privileges.

Thanks for the update.

I would suggest to refer this video as well.

It guides you step by step to recover the password.

Learn how to save login credentials, Set the banner and recover login password via email

https://www-secure.symantec.com/connect/videos/learn-how-save-login-credentials-set-banner-and-recover-login-password-email