You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: I am Debra White, I want to book a flight on 07/18 to meet my friend on his birthday.

ASSISTANT: Ok.

USER: Can you book a return ticket on 07/20?

ASSISTANT: Sure, may I know your airport codes?

USER: My source point is PA-PHL and destination is TX-IAH.

ASSISTANT: May I know your price limit?

USER: My budget is 5000 for flight ticket.

ASSISTANT: There is a Spirit 1001 airline which matches your travelling dates. Shall I proceed with booking?

USER: Sure, you can.

ASSISTANT: Your booking has been confirmed on name of Debra White.

USER: Thank you for booking flight ticket.

ASSISTANT: Thank you for approaching us.