This sample demonstrates the Gantt component with the row drag and drop feature. You can rearrange the gantt rows by using drag icon in left side of gantt column. Here you can perform drag and drop the gantt rows in to required position.
Row drag and drop feature can be enabled by settting allowRowDragAndDrop property as true. In this demo, taskbar drag and drop between rows can be enabled by setting allowTaskbarDragAndDrop as true. More information on the Essential® JS2 Gantt Chart can be found in this documentation section.