You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello,. How can I assist you today?

USER: Please book a ticket from Las Vegas, NV-LAS to Boston, MA-BOS.

ASSISTANT: Sure, we are here to aid you. On which dates would you like me to book a flight ticket for you?

USER: Departure is by 01/23 and 01/25 is return date.

ASSISTANT: Could I have your name please?

USER: I am Mary Johnson.

ASSISTANT: Thanks for sharing your details. There are no flights available on your route.

USER: Thanks for the assistance.

ASSISTANT: Thank you for opting us, hope to serve you again.