You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: I'm planning to visit Philadelphia, can you please book the ticket from HOU to PHL?

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: Sure, my planned departure and return travel dates are 15th and 17th of Feb.

ASSISTANT: Ok, could I have your name please?

USER: My name is Larry Davis.

ASSISTANT: Ok, do you need direct or connecting flight?

USER: I prefer single connected flight to travel.

ASSISTANT: Ok, do you have any other specifications?

USER: No, I don't have any other specifications.

ASSISTANT: Sorry, there is no flight on your requested travelling dates.

USER: Oh! That's ok, thank you for giving the information anyways.

ASSISTANT: You are welcome, have a great day.