You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I be of your service?

USER: As my exams were postponed, I need to change my existing reservation. Can you help me with that?

ASSISTANT: May I please know your name?

USER: I am Anthony Parker.

ASSISTANT: Ok, I will help you. But, I am sorry to inform you that there is no existing reservation available on your name. Sorry for the inconvenience.

USER: Thanks for assisting  me.

ASSISTANT: Thanks for opting us. Have a good day.