You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello. How can I assist you today?

USER: I am Brandon Turner. Please change my existing reservation.

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: I am happy to inform that there is a reservation found on your name. Could you please help me with your new reservation details?

USER: I will depart on 01/12 and will return by 01/14.

ASSISTANT: Ok, may I know your airport codes?

USER: Origin airport code is Houston, TX-IAH.

ASSISTANT: Ok.

USER: Destination airport code is Las Vegas, NV-LAS.

ASSISTANT: Could you please help me with your price limit?

USER: Price limit is 1000.

ASSISTANT: Sorry to inform you that there are no flights found on your requested details.

USER: Thanks for the assistance.

ASSISTANT: Thank you for approaching us, have a nice day.

USER: Thanks.