You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I want to book a ticket from New York to Houston.

ASSISTANT: Sure, can I know your travelling dates?

USER: Travelling dates are May, 13 and May, 15.

ASSISTANT: Ok, let me know your source and destination airport codes?

USER: Airport codes are EWR and HOU.

ASSISTANT: On which name should I reserve the flight ticket?

USER: My name is Ryan Davis.

ASSISTANT: Do you have any connection limit?

USER: I prefer connecting flight.

ASSISTANT: Do you have any other specifications?

USER: I would like to return in the evening.

ASSISTANT: Sorry, there are no flights found on given dates.

USER: Thank you.

ASSISTANT: Thank you for reaching us.