You can always create a new account as admin or edit the current account. In order to do this, you MUST be able to access the database directly, such as via phpMyAdmin.
What I would do is go to the osTicket database, and open the staff table (something like ost_staff). Find the admin account (where the column isAdmin contains a value of 1). Edit this record, and set the value of the passwd column to e00cf25ad42683b3df678c61f42c6bda
Now when you log in, use the username you set, and the password "admin1" (without quotes). This should get you into the system. The VERY NEXT thing you need to do is to CHANGE YOUR PASSWORD!!
The other option is to create a new 'temporary' account from within phpMyAdmin, and set the password to the above value, and set isAdmin to 1, then log in with that account and change the admin password, then delete the temporary account.