You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am very happy to change my existing reservation because my examination was postponed, now I have much time to prepare for the exam.So please help me in modifying my recent reservation.

ASSISTANT: Sure, may I know your name please?

USER: Laura White here.

ASSISTANT: Ok. Sorry, no reservation is found with your data.

USER: It's no a problem. Thanks for checking and giving information.

ASSISTANT: Thank you for choosing us.