You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: Please assist me in booking a flight ticket with single connection.

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

USER: My airport codes are from HOU to DCA.

ASSISTANT: On which dates you like to travel?

USER: I want to travel on Oct 1st and return on Oct 3rd.

ASSISTANT: May I know your name please?

USER: I am Dennis Brown.

ASSISTANT: I am sorry no flights found on your route.

USER: Ok, no problem.

ASSISTANT: Thank you for choosing us.

USER: Thank you.