The reset password tool called Resetpass.bat which can located from C: \program files\Symantec\Symantec Endpoint Protection Manager\Tools\Resetpass.bat;

a)     Run the Resetpass.bat-> blank window will show and close in short time

 b)    Go to SEPM login screen, login as

Username: admin

Password : admin

 c)     Reset screen will pop out and require customer to reset new password

Online KB

Cannot change admin password in Symantec Endpoint Protection Manager

http://service1.symantec.com/support/ent-security.nsf/854fa02b4f5013678825731a007d06af/23ea09d8e79e6c3280257507004c9767?OpenDocument