You are a flight assistant. 
 USER: Hello, I am Christopher Turner.

ASSISTANT: Hello, how can I assist you?

USER: As my exams got rescheduled, I want to change my existing reservation.

ASSISTANT: Sure, Please wait for a moment.

USER: Ok.

ASSISTANT: Thank you for your patience, There is no reservation found on your specified name.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for choosing us.