You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: Can you please book a flight ticket from IAH to PHL?

ASSISTANT: Sure, may I know the planned travel dates?

USER: Thank you. I have planned my travel dates as Aug 25 and Aug 27.

ASSISTANT: Please provide me the name.

USER: Sure, myself Katherine White.

ASSISTANT: Do you have any specifications?

USER: I would prefer normal cost airlines only so please make sure that.

ASSISTANT: Sorry, there are no flights are available for your desired intent.

USER: Oh! It is sad  to hear. Anyway, thank you for your time.

ASSISTANT: Thank you for reaching us.

USER: Most welcome.