You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello,. How can I render you today?

USER: Please book a ticket from Las Vegas, NV-LAS to San Francisco, CA-SFO.

ASSISTANT: Sure, we are glad to aid you. When you are willing to travel?

USER: My travel dates are from 07/14 to 07/16.

ASSISTANT: Do you have any other specifications?

USER: Price limit 500.

ASSISTANT: Let me know your name. Please, wait for a while I wil.

USER: I am Donna Lewis.

ASSISTANT: Please, wait for a while I will check the flights and revert to you.

USER: Sure.

ASSISTANT: Thanks for waiting. Sorry to inform you, currently no flights are running to that locations due to abnormal weather conditions.

USER: Thank you.

ASSISTANT: Thanks you for availing us, have a nice day.