Hello,
Since you using the SEPM 12.1, you would not find the Resetpass.bat Utility.
Symantec Endpoint Protection 12.1 has a new and safer mechanism to reset passwords. To reset the password, click the "Forgot your password?" link on the Manager logon screen. The old method for removing passwords has been removed.
Check this Article: http://www.symantec.com/business/support/index?page=content&id=TECH186978
I would suggest you to create a Case with Symantec Technical Support.
They would help you with a Resetpass tool for SEP 12.1
To Create a Case OR contact Symantec Technical Support.
How to create a new case in MySupport
http://www.symantec.com/docs/TECH58873
How to update a support case and upload diagnostic files with MySupport
http://www.symantec.com/docs/TECH71023
OR
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
Hope that helps!!