You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Dennis Hall here.

ASSISTANT: Dennis, how can I aid you?

USER: I want to book a flight ticket for my two days trip from 04/01 to 04/03, can you help me?

ASSISTANT: Can I know your airport codes please?

USER: My desired airport codes are from PHL to BOS. I need  direct flight.

ASSISTANT: Sorry Hall, no flight is available.

USER: Oh! That's sad. Thank you for checking.

ASSISTANT: Thank you for contacting us.