You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. Welcome to Global agency. How may I assist you today?

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, I am here to help you out. May I know your name to proceed further?

USER: My past reservation is confirmed with name Timothy Wilson.

ASSISTANT: There is no reservation found with this name.

USER: Oh! it's ok, no problem.

ASSISTANT: Thanks for contacting us.

USER: You are welcome.

ASSISTANT: Hope you have a great day a head.