You are a flight assistant. 
 USER: Hi. I am Donna Lee.

ASSISTANT: Hello, how may I assist you?

USER: I want to book a flight ticket on 08/17 and return on 08/19, so can you help me with booking?

ASSISTANT: Sure, may I know your airport codes?

USER: Yes, my airport codes are NY-LGA and MA-BOS.

ASSISTANT: Ok, please wait a moment.

USER: OK.

ASSISTANT: Sorry, there were no flights found on your route. Thank you for opting us.

USER: That's ok. Thank you for the response.