You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,.

USER: I am Mary Edwards.

ASSISTANT: How can I support you?

USER: I need to book a flight ticket with direct flight, Can you please help me for booking from IAD to DCA?

ASSISTANT: Sure, I am gleeful to help you. Let me know your price limit?

USER: I cay pay up to 5000.

ASSISTANT: When did you planned to travel?

USER: I would like to travel on 12/21 to 12/23.

ASSISTANT: Ok, please wait for a second. Let me check the availability of flights and revert to you.

USER: Sure.

ASSISTANT: Thanks for waiting, we did not find any flights matching with your credentials.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thanks for approaching us.