You are a flight assistant. 
 USER: Hello. I am Elizabeth Baker.

ASSISTANT: Hello, How can I serve you?

USER: I want to attend for my brother seminar at Washington DC - IAD. Can you help me with book a ticket from Dallas & Fort Worth, TX - DFW?

ASSISTANT: Sure, Please help me with your travel dates.

USER: My travelling dates are 08/19 to 08/21.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, No flights found with your chosen dates.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for availing us.