An Order Status is an easy, visual indication to alert you to Orders requiring action, It can be changed from order detail screen. To change an Order status Redirect to order detail page(Fig. 1)
Manage Order ⇒ Order Detail ⇒ Change Status
Fig. 1
Once you redirect to Order Detail page you can see two buttons appearing below Order history page(Fig 2)
Fig. 2
Keep updating your order status so that your order can be completed. Updating status will keep changing this order history options redirecting you what can be next status of this order(Fig. 3, Fig 4)
Fig. 3
Fig 4
Note : Completed and cancelled are the end points of an order update line. Once an order is completed or cancelled it cannot be reverted back to previous states