You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I am Patricia Roberts. I want to book a flight ticket from DC-IAD to NV-LAS. Can you help me?

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

USER: 07/09 and 07/11 are my travelling dates.

ASSISTANT: Do you have any specifications?

USER: I would like to depart in the evening with a connecting flight.

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

USER: No issue. Thank you.

ASSISTANT: Welcome. Have a nice day.