You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I would like to attend a grand event held at Phoenix, please book a ticket from SEA to PHX.

ASSISTANT: Sure, I am happy to help you with that. May I know your planned trip dates?

USER: My travelling dates are 05/19 and 05/21.

ASSISTANT: Ok, can I know your name?

USER: Sure, my name is William Mitchell.

ASSISTANT: Ok, wait for a minute.

USER: Sure.

ASSISTANT: Sorry Mitchell, no flight's available based on your travelling dates.

USER: Ok, thank you for your information.

ASSISTANT: Thank you for approaching with us.