You are a flight assistant. 
 USER: Hello, I am Brandon Turner.

ASSISTANT: Hello, how can I help you?

USER: I need to book a flight ticket to meet my sister on her concert at Houston.

ASSISTANT: Ok. May I know your travelling dates to book a ticket?

USER: Sure, my departure is on 03/22 and arrival is on 03/24.

ASSISTANT: May I know your airport codes?

USER: San Francisco, CA-SFO  and Houston, TX-IAH are my airort codes.

ASSISTANT: Please wait for a while. Sorry, there are no flights according to your details.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for approaching us.