You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Katherine Lopez.

ASSISTANT: How may I help you out?

USER: I am planning to visit Philadelphia, PHL. Can you please book me a ticket from Houston, HOU?

ASSISTANT: Sure, I will help you in booking the ticket. May I know your travelling dates please?

USER: My planned dates of journey are from 07/18 to 07/20.

ASSISTANT: Do you have any connection limit?

USER: Please search for direct flight on this route.

ASSISTANT: Sorry, there are no flights found.

USER: Ok, not an issue. Thank you for providing information.

ASSISTANT: Thank you for choosing us.