You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I want to visit Boston, can you book a ticket please?

ASSISTANT: Sure, may I know your airport codes?

USER: My airport codes are IAH to BOS.

ASSISTANT: Can you provide me your travel dates?

USER: My travel dates are 07/15 and 07/17.

ASSISTANT: May I know your name?

USER: My name is Larry King.

ASSISTANT: Sorry Larry King, there is no flight available as per your requirements.

USER: Ok, thank you for checking.

ASSISTANT: Thank you for reaching us.