You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. May I know your good name please?

USER:  My name is Scott Allen.

ASSISTANT: How can I help you for today?

USER: Actually my examination is postponed, so I need to change my existing reservation. Can you please help me to change the reservation?

ASSISTANT: Sure, please give me a second.

USER: Ok.

ASSISTANT: Thanks for waiting. Sorry, there is no existing reservation on your name.

USER: Its ok, thank you.

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

USER: Thank you.