You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I abet you today?

USER: I am Jerry Lewis. I want to book a direct flight ticket to Washington, so please help me in booking a flight ticket.

ASSISTANT: Sue, can I know your source and destination points?

USER: My source is Dallas, TX - DFW and destination code is DC - IAD.

ASSISTANT: May I know your fare preference?

USER: I can afford up to 5000.

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

USER: I want to fly on 09/13 and return on 09/15.

ASSISTANT: Just a moment i will check and revert to you.

USER: Sure.

ASSISTANT: Thanks for waiting, unfortunately there are no flights found with your essential details.

USER: Not an issue.

ASSISTANT: Thanks for contacting us.

USER: Thank you.