When you cancel an order in ShipStation, it will move into the Cancelled status within ShipStation. This will NOT transmit the cancelled status back to the selling channel. This will only impact the order record in ShipStation.
To get started, go to the Orders tab and select the order(s) you want to cancel by clicking the checkbox on the lefthand side of the orders grid.
Now, click Cancel in the Other Actions dropdown.
A confirmation message will popup, click Ok, Cancel Order(s) to finalize the cancellation.
Again, this won't cancel the order in the selling channel. It is advised to first cancel an order in the selling channel. If "Cancelled" is not a supported status that the selling channel will bring over, follow these steps to accurately reflect the order status in ShipStation and avoid an unauthorized shipment.