You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Robert Lewis here. I want to attend a Seminar in Houston. Can you please help me for booking the flight ticket?

ASSISTANT: Ok, I will help you with your concerns.

USER: Thanks.

ASSISTANT: May I know the airport codes to book a flight?

USER: My airport codes are from CLT to HOU.

ASSISTANT: Ok, I need the travel dates your prefer to check. Can I know?

USER: My travelling dates are from 08/22 to 08/24.

ASSISTANT: Ok, please wait a moment. Thank you for waiting.

USER: My pleasure.

ASSISTANT: I am sorry, there are no flights available at that dates.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for choosing our agency.