You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me in changing my existing reservation, which I have done earlier?

ASSISTANT: Sure, I am here to help you. Can I know your name?

USER: Thank you. My name is Jason Johnson.

ASSISTANT: Please wait for a moment.

USER: Ok, sure. I will be waiting for your response.

ASSISTANT: Sorry, no reservation found on your name.

USER: Ok, no problem. Thank you for the information.

ASSISTANT: Thank you for reaching us, have a nice day.