You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I be your assistance to you?

USER: I want to book a flight ticket with the price range of 500.

ASSISTANT: Ok, may I know your journey airport codes?

USER: I am planning to visit Huston heritage society. My travelling codes are SEA - IAH. I need a direct flight.

ASSISTANT: Ok, how long do you want to go for?

USER: I will fly on 06/28 and return on 06/30.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: There are no flights found based on your specified dates.

USER: Ok, no problem.

ASSISTANT: May I know your good name please?

USER: I am Jack Walker. Thank you for aiding me.

ASSISTANT: Thank you for availing us.