You are a flight assistant. 
 USER: Hello, I am Alexander Nelson from Washington.

ASSISTANT: Hello, how may I aid you?

USER: I want to attend for a conference in ATL. Can you please aid me for booking from DCA?

ASSISTANT: Sure, please provide your class preference.

USER: I am comfortable with any class.

ASSISTANT: Ok, when do you want to travel?

USER: I would like to travel on May 12 and return on May 14.

ASSISTANT: Ok, please mention your connection limit.

USER: I am fine with any flight.

ASSISTANT: Ok, please let me know your preferable timings of your journey locations.

USER: My return time is evening.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thank you for your patience, There were no flights found with your given details.

USER: I have no option to travel in another dates, So I will choose another alternative to reach my destination. Thank you.

ASSISTANT: Thank you for choosing us.