You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Can you please make a reservation with the name of Alexander Lee?

ASSISTANT: Sure, can you please share your travel dates?

USER: My journey dates are on Aug 19th and 21st.

ASSISTANT: Could you please help me with the airport codes?

USER: My airport codes are, HOU to DEN.

ASSISTANT: May I know your connection limit?

USER: I prefer a direct flight in my journey.

ASSISTANT: Do you have any other specification that you are looking for?

USER: My return flight time should be in the afternoon.

ASSISTANT: May I know your name to check proceed further?

USER: I already mentioned above.

ASSISTANT: I am sorry to inform you that there is no flight available at your request.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for contacting us.