You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I reserved a ticket to Fort Worth for this weekend, but I want to change my reservation because my exam is postponed. Can you help me?

ASSISTANT: Sure, I will help you to change your reservation.

USER: Thank you.

ASSISTANT: Give me a moment.

USER: Ok.

ASSISTANT: May I know your name to check your previous reservation.

USER: I reserved the ticket on the name Sharon Hill.

ASSISTANT: Ok. Sorry, there is no reservation found on your name to change your previous reservation.

USER: That's ok, thank you for your information.

ASSISTANT: Welcome. Have a nice day.