Hi [NAME],   This link should be able to help you reset the password:  [URL]   Here an alternative solution, steps are the same for S4148F.  [URL]
I have two S4148F-ON connected with a VLT domain.  i do not have the admin (or any) password to log into these.  i can schedule downtime to do the password recovery.  does anyone have a pointer to a current guide for doing this?  
S4148F-ON password recovery