You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I abet you?

USER: Owing to an emergency, I want to change my existing reservation with the name of Helen Green.

ASSISTANT: Ok.

USER: Can you help me in changing my reservation?

ASSISTANT: Sure, I will help you. Please wait a minute.

USER: Thank you.

ASSISTANT: Thanks for your time, we did not find a reservation on your name.

USER: Ok, no problem. Thank you for your response.

ASSISTANT: Thank you for approaching us.