You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what can I do for you?

USER: I want to go Boston, MA-BOS to meet my parents.Can you please help me for booking the flight ticket?

ASSISTANT: Sure, Can I have your name please for booking your ticket?

USER: My name is Helen Smith.

ASSISTANT: Smith, can I know your source airport code and your travelling dates please?

USER: The source code is from MA-BOS. The travelling dates are from 07/31 to 08/02.

ASSISTANT: Sorry, I did not found any flight which is travelling to your destination on your provided dates. Do you have any other preferable dates to travel?

USER: Ok, no problem. No, I don't have any other dates. Thank you for your information.

ASSISTANT: It's ok, make your plan on some other day and meet us again.

USER: Sure.

ASSISTANT: Thank you, have a nice day.