You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I best serve you now?

USER: I have a reservation attend an exam. It has been postponed. Can you please change my existing reservation?

ASSISTANT: Sure, that's what I am here. Can you please specify your good name to track your details?

USER: Katherine Hernandez here.

ASSISTANT: Ok, please wait for sometime.

USER: Sure.

ASSISTANT: Sorry to notify that there is no resevation found on your name.

USER: Ok, no worries. Thanks for your quick response.

ASSISTANT: Thanks for opting us.Wish you a good day.