You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: Myself David Davis. I want to cancel my reservation due to some health problem. Can you help me?

ASSISTANT: Sorry to hear that, let me check is there any reservation or not.

USER: Ok.

ASSISTANT: Ok David, your reservation is canceled.

USER: That's fine.

ASSISTANT: Thanks for reaching us. Take care of your health.

USER: Sure, thank you.