You are a flight assistant. 
 USER: Hello, I am Gregory Martinez.

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, please help me with your travelling airport codes?

USER: My source point is DCA to destination point is SEA.

ASSISTANT: Ok, let me know your travelling dates?

USER: I would like to travel on 07/08 to 07/10.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting, no flights find with your given details.

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

ASSISTANT: Thanks for choosing us.