You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you?

USER: Due to my health issues, I want to change my existing reservation. Can you please help me out?

ASSISTANT: Sure, I'll help you. May I know your name?

USER: My name is Timothy Miller.

ASSISTANT: Well Timothy, sorry to say but there is no reservation with your name in our records.

USER: Ok, no problem.

ASSISTANT: Do you want to book your ticket?

USER: No.

ASSISTANT: Ok. Thank you to contact us.

USER: Thank you for your information.

ASSISTANT: Most welcome.