You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I help you?

USER: I am Matthew Young. Could you help me in booking a flight ticket from Houston to Los Angeles within a price limit of 200?

ASSISTANT: Sure. May I know your travelling dates?

USER: I will start on 05/26, return on 05/28.

ASSISTANT: Can you share me your airport codes?

USER: My source and destination airport codes are HOU, LAX.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: Thanks for waiting, There are no flights found on your data.

USER: No problem, thank you.

ASSISTANT: Thank you.