You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am George Lee. Due to my health problem I want to change my reservation, can you please help me to change my reservation?

ASSISTANT: Sure, please wait for a moment to check your reservation details. Sorry to say, no reservation found on your name.

USER: That's fine. Thank you for your service.

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