The first step in ReST API design is deciding on the 'language' of the conversation.
The second step focuses on understanding the user's intentions.
The third step is to craft a dialogue.
Framing the cancellation process more thoughtfully can capture the humane aspect of the dialogue.
The cancellation process could be designed through a POST to a 'CancelledOrders' endpoint with a reason code or message.
CancelledOrders have advantages of reSTful purity, state representation, and extensibility.
An order canceller approach maintains the focus on the Order resource and is simpler.
The option to choose between resource-oriented and action-oriented approach depends on whether to prioritize conceptual clarity or operational simplicity.
The noun chosen should align with how the domain experts and API consumers naturally think.