You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: I want to book a ticket from DFW to IAD, can you please help me?

ASSISTANT: Sure, could you please let me know your dates of journey?

USER: My travelling dates are on Apr 26 and Apr 28.

ASSISTANT: Please let me know your name?

USER: My name is Charles Allen.

ASSISTANT: Are you looking for any other help from my side please?

USER: I need a direct flight.

ASSISTANT: Ok, wait for a mean while.

USER: Sure.

ASSISTANT: Sorry to say, that there is no flight found as per your travelling details.

USER: Ok, not a problem. Thank you.

ASSISTANT: You are welcome.