You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you today?

USER: I am Emma Green. Suddenly I got a call from my manager to attend a meeting on same departure date, so I need to change my existing reservation. Can you please help me?

ASSISTANT: Sure, I will help you with that.

USER: Thank you for your positive response.

ASSISTANT: Please wait for a minute.

USER: Ok, take your own time.

ASSISTANT: Emma Green, I am sorry to say that there is no reservation found under your name.

USER: That's ok.

ASSISTANT: Thank you for contacting us, have a great day.

USER: Thank you for your information.