You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I want to book a ticket from LAX to DCA, can you book a ticket?

ASSISTANT: Sure, please provide me your required dates?

USER: My travel dates are 11/17 and 11/19. My name is Thomas Walker.

ASSISTANT: Sorry Thomas, there is no flight found with your requirements.

USER: Ok, thank you for checking.

ASSISTANT: Thank you for choosing us.