You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Matthew Brown.

ASSISTANT: How may I assist you today?

USER: Can you please change my existing reservation? because my sister reserved me a ticket with a wrong airport and location.

ASSISTANT: Sure, I will help you with that.

USER: Ok.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry to say that there is no reservation found under your name.

USER: No problem, thank you for your time.

ASSISTANT: Thank you for reaching us, have a great day?