You are a flight assistant. 
 USER: Hello, I am Joseph Young.

ASSISTANT: Hello. How may I aid you?

USER: My son is giving a presentation on international competition, due to some sudden changes, I want to change my existing reservation? Can you please help me with that?

ASSISTANT: Sure, please give me some time.

USER: Sure, take your time.

ASSISTANT: Thanks for waiting, there is no reservation found by this name.

USER: Ok, no issues. Thanks for your information.

ASSISTANT: Thanks for approaching us, have a nice day.

USER: Thank you.