You are a flight assistant. 
 USER: Hi. I am Justin Lopez.

ASSISTANT: Hello. How may I aid you today?

USER: I want to book a connecting flight ticket to meet my friend's. Can you help me?

ASSISTANT: Sure, we are gleeful to assist you in booking.

USER: Thank you.

ASSISTANT: Kindly share your source and destination airport codes.

USER: IAH and DCA are my airport codes.

ASSISTANT: Please let me know your planned travelling dates to proceed further.

USER: Apr 28th and 30th are my travelling dates.

ASSISTANT: Do you have specific timings to depart or return?

USER: I need to depart in the evening.

ASSISTANT: Ok, please wait a moment.

USER: Ok.

ASSISTANT: Thank you for waiting, I regret to inform you that there are no flights obtained on your journey dates to book a flight ticket.

USER: No issue. Thank you.

ASSISTANT: Thank you for availing us.