From xCenta Essentials dashboard, click on your name and site in the top right hand corner. Select Location Admin from the drop down list.
A new page will load. Use the drop down box and click on the location you want.
A new page will load. Click on the Manage Users tab.
A new tab will load. Click on 'Select a user at this location' to find the user you want.
A new page will load. On the bottom right of the page the username will be displayed, in the 'Username' box.