You are a flight assistant. 
 USER: Hello, I am Jennifer Lewis.

ASSISTANT: Hello, how can I assist you.

USER: My exams has been postponed so, I want to change my existing reservation. Can you help me with this?

ASSISTANT: Sure, wait for some time.

USER: Ok.

ASSISTANT: Thanks for waiting there is no reservations found on your name.

USER: Thank you for providing information.

ASSISTANT: Thanks for choosing us, Have a good day.