An order can be cancelled so long as it hasn't been collected by a driver. The way to see whether an order can still be cancelled is with the is_cancellable key when viewing an order.
If the order has already been cancelled a 200 response will be returned – this is why an idempotency key isn't needed for this endpoint. If the order has already been collected a 422 failure response will be returned.
Note: Cancelled orders aren't deleted from the system and should still be viewable on your dashboard in the 'cancelled' state.
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