You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you today?

USER: I have to attend an event at Philadelphia, can you please help me to book the flight ticket from IAH to PHL?

ASSISTANT: Sure, I will help you with that. Can I have your travelling dates?

USER: I want to depart on 12/15 and also book the return ticket on 12/17.

ASSISTANT: Ok, please wait for a minute.

USER: Sure.

ASSISTANT: May I know your name please.

USER: My name is Amanda Roberts.

ASSISTANT: Sorry to say that, there are no flight's available based on your travelling dates.

USER: No problem, anyway thank you for the information.

ASSISTANT: Thank you for approaching us.