You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I am planning change an existing reservation, due to health issue. Can you please help me out?

ASSISTANT: I am sorry to hear that. I will help you. Please help me with your name.

USER: My name is Nicholas Collins.

ASSISTANT: Please allow me a minute.

USER: Sure.

ASSISTANT: Nicholas Collins, I regret to inform you that there is no booking done on your name.

USER: That's fine, thank you for your service.

ASSISTANT: Thank you for reaching us. Have a awesome day!.