You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I serve you at this moment?

USER: I am Richard Lee here. I would like to change my existing reservation, which is done recently. Can you please help me out in changing my reservation?

ASSISTANT: Sure, I am here to help you. Please wait for few minutes.

USER: Thank you for considering my request and I will wait for your response.

ASSISTANT: There is no existing reservation found on your name in our records.

USER: Not a big problem, anyway thank you for the information.

ASSISTANT: Thank you for reaching us.