If you need to cancel an existing order, here are the steps.

1. Open the order by clicking on the order #.

2. Under Actions click on "Cancel Order"

3. Enter comments for canceling the order. You can also select what lines to cancel in case it is a partial cancellation of the order.

4. After entering the comments, click on "Cancel" to cancel the order.

5. The status of the order would be then updated to Cancelled.