you could probably walk to the server and log into it at the keyboard and log on with "user", and change your password that way
HOWEVER - i don't understand how you're accessing a server, by a public ip address, when you're in the same building as it. not only is it incredibly insecure to run netbios shares over the internet, but a lot of internet service providers block it from working.
in your case, it works - but to get your password changed you're going to have to go to the physical machine and log in (if it lets you), or ask the person in charge.
we tried to break in the best i can help you to do - but there's no other option at this point, you need more control over the server. physically, or ask whoever is in charge
