You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I want to change my existing reservation due to postpone of my exams. Can you help me in that?

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

USER: Ryan Nelson here.

ASSISTANT: Ok, please wait for a moment.

USER: Ok.

ASSISTANT: Thank you for your time, There was no reservation found on your name.

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

ASSISTANT: Thank you for reaching us.