You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Myself Michael Hill, will you help me in booking the flight ticket from DCA to IAH?

ASSISTANT: Sure, I will help you to book a flight ticket. Can you please share me your travelling dates?

USER: My preferable journey dates are Aug 04 and Aug 06.

ASSISTANT: Please give me a moment.

USER: I need a flight with single connection and my depart time must b in evening.

ASSISTANT: Sorry, as per your requirement no flights are available on your particular travel dates.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for reaching us, have a nice day.