You can undo project setting check-out even from a different machine.
To undo a check-out on a different machine
The Project Settings Check Out dialog box is displayed. If this is a collaboration project and the project settings have been checked out, an informational note at the bottom of the dialog box shows who has the settings checked out. Hover over "on another machine" to display more information about the check-out.
To force an undo check-out
The Project Settings Check Out dialog box is displayed. If this is a collaboration project and the Project Settings have been checked out, an informational note at the bottom of the dialog box shows who has the settings checked out.
An informational dialog box is displayed, showing the username of the person who has the drawing checked out.