You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: I am Steven Wright from Washington. I would like to travel from DCA to LAS for an important meeting, can you please search is there any flight available for me?

ASSISTANT: Sure, may I know your dates of travel?

USER: Thank you for your response, I want to take off on May 31 and book my return ticket also on June 02.

ASSISTANT: Do you have any specifications?

USER: I want a business class flight so please check with this.

ASSISTANT: Ok, please wait a minute.

USER: Ok.

ASSISTANT: Sorry, there were no flights found on your class preference.

USER: Oh! It's ok no problem. Thank you for your information.

ASSISTANT: Thank you for opting us.