You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I want to visit Lincoln memorial in Washington, can you book a ticket please?

ASSISTANT: Sure, may I know your airport codes to help you?

USER: My airport codes are from LGA to IAD.

ASSISTANT: Will you please share your trip dates too.

USER: My travel dates are 10/04 and 10/06.

ASSISTANT: May I know your name, in the mean while?

USER: I am Justin Taylor.

ASSISTANT: Thanks for giving your name, there is no flight for you according to your information.

USER: Not an issue, I will try another way to complete my trip. Thank you for checking.

ASSISTANT: Welcome, have a nice day.