You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you now?

USER: I am Charles Green. Help me to book a ticket from LAX to HOU, can you book a ticket?

ASSISTANT: Sure Charles Green, can I have your travel dates please?

USER: My travelling dates are on Apr 06 and Apr 08.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Sorry Charles Green, no flight is available to you on your dates.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us, have a good day.