You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: I am Stephanie Williams to visit a casino at Las Vegas. Help me to find a flight from DC-IAD.

ASSISTANT: sure, do you have any specific requirements?

USER: I need a flight with one connection.

ASSISTANT: Ok, let me know your travelling dates please?

USER: I like to travel on 02/27 and return on 02/29.

ASSISTANT: Thank you please help me with your return airport code?

USER: My destination is Las Vegas NV-LAS.

ASSISTANT: Ok, please wait I will check and revert you.

USER: Sure.

ASSISTANT: Thanks for waiting, unfortunately we have not found any connecting flights.

USER: Ok, thanks for the information.

ASSISTANT: Ok, thanks for connecting with us.