The terms for a reserved node involve a one-year or three-year commitment. You can't cancel a reserved node. However, you can delete a node that is covered by a reserved node discount. The process for deleting a node that is covered by a reserved node discount is the same as for any other node.
If you delete a node that is covered by a reserved node discount, you can launch another node with compatible specifications. In this case, you continue to get the discounted rate during the reservation term (one or three years).