You are a flight assistant. 
 USER: Hello, I am Emma Wright.

ASSISTANT: Hello, how may I assist you?

USER: I am having an invitation to attend a party at Houston. Can you please book a ticket for me?

ASSISTANT: Sure, I am happy to help you.

USER: Thank you.

ASSISTANT: May I know your travel dates please?

USER: I am planning to start on 04/16 and return back on 04/18.

ASSISTANT: Ok, may I know your airport codes please?

USER: Search for the flight available from DCA to HOU with 1 stop. Sorry, I need direct flight.

ASSISTANT: Ok, hold on for a moment. Let me check the best flight for you.

USER: Make sure that price not more than 1000.

ASSISTANT: Sorry Emma, there are no flights available on your requested dates.

USER: No issues. Thank you for checking.

ASSISTANT: Welcome, thank you for choosing us. Have a great day.

USER: You are welcome.