You don't unless you're logged in as admin to begin with. Well, there is a way to change passwords with a little utility you boot from floppy, but I'm not going to tell you what it is as I have serious doubts that your intentions are legitimate.
Anyways, log on to your admin account, any account with admin rights, and remove the password via the control panel.
hey im asking bcause i know someone with the problem.ok.How can u manage a pc that you dont even have admin rights ?