Method 1: Reset Admin Password using the SEPM Console
Note: This procedure only works for the default "admin" username. If you created a custom administrator username and forgot it, you must log in with another administrator account to reset it, or reinstall the management server. symantec endpoint protection manager reset admin password
If you’d like, I can:
EmbeddedDBRecover.exe utility (located in the SEPM installation folder, e.g., C:\Program Files (x86)\Symantec\Symantec Endpoint Protection Manager\bin) to access the internal database.