First you'll need RTC client. Open RTC client and open the "Team Artifacts" view. Expand "Repository Connections" within the "Team Artifacts" pane. Right-click on your repository and select "Administer --> Open Users...". Enter the name of the user whose password you'd wish to reset. Hit the "Select" button and click "OK" when finished. This will open a new tab within RTC displaying that particular user's properties. It is here where you can click the "Reset Password..." button to reset that user's password.