You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Frank Mitchell here.

ASSISTANT: Frank, how may I help you?

USER:  I would like to travel from LAS to PHL for business meeting, can you please book the flight ticket?

ASSISTANT: Please share your itinerary dates.

USER: Sure, I want to travel on 02/11 and return on 02/13.

ASSISTANT: Please hold on for a moment.

USER: Sure.

ASSISTANT: Sorry, no flight found.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for choosing us.