You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what is your good name?

USER: I am Dennis Hall.

ASSISTANT: Ok Hall, what can I do for you?

USER: My exams have postponed so I want to change my existing reservation.

ASSISTANT: Sure.

USER: Can you please help me with this?

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry Hall, there is no reservation found with your name.

USER: That's fine.

ASSISTANT: Thank you for contacting us.

USER: Thank you for your time.