You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: I have planned a surprise for my parents in Chicago, ORD. Can you avail me to book a flight ticket?

ASSISTANT: Sure, I am here to help you in booking. Can you please share your travel dates?

USER: My travel dates are Feb 06 and 08.

ASSISTANT: Ok, may I know your source airport code?

USER: My source is from Philadelphia, PHL.

ASSISTANT: May I know your name for further process?

USER: Charles Martin here.

ASSISTANT: Sorry, no flights are available on your preferable on your travel dates.

USER: Ok, thank you.

ASSISTANT: Thank you for reaching us, have a nice day.