You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,. How may I assist you?

USER: I am Emma Wilson. I want to book a flight ticket within a price limit of 200 to meet my parents in Las Vegas.

ASSISTANT: Please mention your travelling dates?

USER: I will start on 06/26, return on 06/28.

ASSISTANT: Please specify your travelling codes?

USER: My source and destination airport codes are TX - HOU, NV - LAS. I want a direct flight.

ASSISTANT: No flights found according to your requirement.

USER: No problem, thank you.

ASSISTANT: Thank you.