You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: I want to change my existing reservation due to some health issues, can you please help me in this intent?

ASSISTANT: Sure, can you help me with your name?

USER: Sure, my name is James Lewis.

ASSISTANT: Please wait for a moment.

USER: Sure, take your time.

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

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

ASSISTANT: Thank you for choosing us, have a nice day.