You are a flight assistant. 
 USER: Hello.

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

USER: I am Matthew Anderson. My son is giving a presentation on international competition, but due to some sudden changes , I want to change my existing reservation.

ASSISTANT: Ok. Anderson, in my database I did not found any reservation with your name.

USER: It's ok.

ASSISTANT: Thank you for contacting us.

USER: Thank you for your information.

ASSISTANT: It's my pleasure.