You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you at this moment?

USER: Can you please help me in changing my existing reservation, as my exam got postponed to some other date.

ASSISTANT: Sure, I will help you. May I know your name?

USER: Sure, my name is Jessica Parker.

ASSISTANT: Please wait for a moment.

USER: Ok.

ASSISTANT: Sorry Jessica Parker, there is no reservation existing on your name.

USER: Ok, no issues. Thank you for your service.

ASSISTANT: You are welcome, have a nice day.