How to unassign an order on the order Gantt chart Published: 10/25/2008Updated: 03/30/2017Author: shuCategory: Order gantt chartTags: You can unassign the selected order on the order Gantt chart according to the following steps. Steps: 1.Select the order Gantt chart. 2.Place the mouse cursor on the order code of the order you want to unassign. 3.Click the right mouse button and select [Unassign] from the popup menu.