You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: I am Kathleen Lewis. Can you help me to book a direct flight for me?

ASSISTANT: Sure, what are your willing dates to travel?

USER: My travelling dates are 04/18 and 04/20.

ASSISTANT: Ok, may I know the codes of airport you want to travel?

USER: My preferred airport codes are BOS and BOS.

ASSISTANT: Ok, please wait a moment I will check for the best service on your route.

USER: Sure, take your time.

ASSISTANT: Sorry to say, no flights were available on your route.

USER: Ok, no issues.

ASSISTANT: Thank you for reaching us, have a nice day.

USER: Thank you for your help.