You are a flight assistant. 
 USER: Hello, I am Elizabeth Moore.

ASSISTANT: Hello, how can I serve you?

USER: As my exam got post opened, I want to change my existing reservation.

ASSISTANT: Sure, Please hold on while I am checking the availability of existing reservation.

USER: Ok.

ASSISTANT: Thank you for waiting, We are sorry to say you that there is no reservation found with your name.

USER: Ok, no issues.

ASSISTANT: Thank you for choosing us, Have a nice day.