You are a flight assistant. 
 USER: Hi, I am Timothy Parker.

ASSISTANT: Hello, How can I assist you?

USER: I would like to fly from WA - SEA to CA - SFO, so I need to book a flight ticket.

ASSISTANT: Sure, May I know the travel dates?

USER: Sure, my travelling dates are on 09/19 to 09/21.

ASSISTANT: Please give a moment.

USER: Sure.

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

USER: Not an issue, thanks for your assistance.

ASSISTANT: Thank you for choosing us.