You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Due to some health issue, I am unable to travel so please change my existing reservation. Can you please help me with this?

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

USER: Sure, I am Ashley King.

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

USER: Ok, Thank you for your help.

ASSISTANT: Thank you.