You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: Owing for an emergency, I want to cancel my flight reservation. Can you please help me?

ASSISTANT: Ok.

USER: Thank you.

ASSISTANT: Can I know your name?

USER: My name is Sarah Nelson.

ASSISTANT: Sorry, there is no reservation by name Sarah Nelson.

USER: No problem, thank you for checking.

ASSISTANT: Thank you.