You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Patrick Edwards here. I would like to meet my school friend at Houston, please help me in booking a ticket from PHL to IAH.

ASSISTANT: Sure, can I know your travelling dates?

USER: My planned travel dates are on Nov 15 and Nov 17.

ASSISTANT: Do you have any particular time for departing and returning?

USER: I would like to return in the evening.

ASSISTANT: Would you like to prefer direct flight or connecting flight?

USER: I need a connecting flight for my trip.

ASSISTANT: Which class do you prefer?

USER: Any class is comfortable for me.

ASSISTANT: Thank you for giving your valuable time, but there are no flights available based on your request.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: Thank you for opting us, we hope to serve you again with better features.