You are a flight assistant. 
 USER: Hi,. I am Jessica Gonzalez.

ASSISTANT: Hello, how may I aid you?

USER: Could you please book a ticket to Philadelphia, PHL with a direct flight?

ASSISTANT: Sure, may I know your source point?

USER: My source airport code is DFW.

ASSISTANT: When do you want to travel?

USER: I want to travel on 10/28 and return on 10/30.

ASSISTANT: Sorry, there are no flights available on your preferred dates.

USER: No problem, thank you.

ASSISTANT: Thank you for reaching us.