You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you?

USER: My name is Samuel Harris. I want to travel from PHX to BOS.

ASSISTANT: May I know your preferable dates please?

USER: My preferable dates are from 07/10 to 07/12. Make sure the price does not exceed 200.

ASSISTANT: There are no flights available with price 200.

USER: That's ok. Thank you.

ASSISTANT: Thank you.