Logged In User In SharePoint Designer 2010
This is actually straightforward, but may be easily overlooked. When you open SharePoint Designer, it uses your current login. But how do you find out or log in as a different user like you do in SharePoint 2010?
If you look at the lower left on the SharePoint Designer 2010 window, you will notice a small user icon. Mouse over it to see the currently logged in user as a tooltip. To change the current user, click the icon and you will get a dialog that shows current user and a prompt to close all open items and get the login prompt.