You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I am Sarah Thomas and I need to book a direct flight to ORD from LAS. Can you make a reservation with fare 5000?

ASSISTANT: Sure, I will help you to book a flight ticket. Can you please share me your travelling dates?

USER: Sure, I need to depart on Jul 19 and Jul 21.

ASSISTANT: Please allow me a moment.

USER: Sure.

ASSISTANT: Sorry, no flights are available on your route.

USER: Ok, no issues. Thank you for your help.

ASSISTANT: Welcome, have a nice day. Thank you for choosing us.