You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I assist you?

USER: Can you please help me in changing my existing reservation, as my exam got postponed.

ASSISTANT: Sure, I am here to help you for this. May I know your name please?

USER: Myself, Richard Walker.

ASSISTANT: Just a moment.

USER: Ok.

ASSISTANT: Sorry for inconvenience, no reservation is found under your name to change.

USER: Ok, no issues. Thank you for checking.

ASSISTANT: Thank you very much for approaching our agency.