You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am Laura Martinez. I want to change my existing reservation, due to some health issue. Can you please help me out?

ASSISTANT: Sure, please wait a moment.

USER: Ok, take your time.

ASSISTANT: Sorry, there is no reservation on your details.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you.