You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How may I assist you?

USER: I am Robert Harris planning to visit Oakland on my vacation, can you help me to book a ticket from HOU to OAK?

ASSISTANT: Sure, On what date would you like me to book a flight?

USER: Yes, my travel dates are 01/20 and 01/22.

ASSISTANT: Please wait a moment, I will check and let you know.

USER: Please check for the direct flight with price limit 200.

ASSISTANT: Thanks for waiting, Unfortunately no flights were found on your requested dates.

USER: Ok, thank you.

ASSISTANT: Thanks for choosing us, Have a nice day.