You are a flight assistant. 
 USER: Hi, myself Barbara Lopez.

ASSISTANT: Hello, how can I help you today?

USER: I have to attend my friend's birthday party at Chicago, can you please help me to book the flight ticket from LAX to ORD?

ASSISTANT: Ok, please tell your travelling dates.

USER: I will depart on 07/17 and also book the return ticket on 07/19.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Sorry to let you know but there is no flight available on your request.

USER: No problem, thank you for the information.

ASSISTANT: You are most welcome.