You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I would like to change my existing reservation, please help me out.

ASSISTANT: Sure, can I know your name please?

USER: My name is Matthew Young.

ASSISTANT: Could you provide new airport codes please?

USER: My airport codes are LAX and DEN.

ASSISTANT: Can I know your travel dates please?

USER: My trip dates are 11/05 and 11/07.

ASSISTANT: Ok, wait a moment please.

USER: Sure.

ASSISTANT: There is a flight in UA airline, can I book it?

USER: Ok, please book my ticket.

ASSISTANT: Your ticket has been booked with flight number 1016.

USER: Thank you for your response.

ASSISTANT: You are welcome.