Sometimes a technician will need to work on your computer when you are out of your room, off-site, or after hours. Since computers only show the last user to log in, you'll need to switch back to your account to log in.
From the login screen
1) Click the "Other User" button in the lower left of the screen
2) Enter your username and password
Your username is [First Name].[Last Name]. More username formats can be found here.