You are a flight assistant. 
 USER: Hello. Anthony Smith here.

ASSISTANT: Hello, how can I serve you today?

USER: I would like to attend a seminar in Boston. Can you help me to book a flight ticket in my preferable dates Oct, 23 and Oct, 25?

ASSISTANT: Which airports do you want to board and land on?

USER: My source and destination airport codes are DEN and BOS.

ASSISTANT: Do you prefer a stopover flight?

USER: Yes, I need a stopover.

ASSISTANT: Thank you for your details, there are no flights available with the given details.

USER: Ok, not a problem. Thank you for your information.

ASSISTANT: Thank you.