You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you today?

USER: Could you please change my existing reservation due to postpone of my exams?

ASSISTANT: Ok, I am glad to help you with that. May I know your good name?

USER: My name is Emma Clark.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: Sorry to say that, there is no reservation found on your name in our database.

USER: Not a problem, thank you for checking.

ASSISTANT: Thank you for choosing us. Have a nice day.