You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: Can you please help me in booking a direct flight to Houston?

ASSISTANT: Sure, may I know your airport codes?

USER: Sure, my airport codes are PHL and IAH.

ASSISTANT: Please provide me your travelling dates.

USER: Ok, my travelling dates are Dec 01 and Dec 03.

ASSISTANT: Any specifications needed for this booking.

USER: I need return flight in the evening.

ASSISTANT: May I know your connection limit?

USER: I need a direct flight for my journey.

ASSISTANT: On which name shall I reserve flight ticket?

USER: Reserve the flight ticket under my name Rachel Hernandez.

ASSISTANT: Sorry, there are no flight tickets available on your journey dates.

USER: Not a problem, anyways thank you for the information.

ASSISTANT: Thank you for reaching our service.