You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I support you for the day?

USER: I am planning to visit Denver Zoo with my children, can you help me with booking a flight ticket?

ASSISTANT: Sure, I am here to help you. May I know your travelling dates?

USER: My trip dates are 05/28 and 05/30.

ASSISTANT: Can you Please help me with your airport codes?

USER: I would like to fly from OAK to DEN.

ASSISTANT: Do you have any other specification?

USER: Yes, I need a stop over.

ASSISTANT: May I know your good name?

USER: Mary Taylor.

ASSISTANT: Sorry, we found no flights with your specifications.

USER: That's ok.

ASSISTANT: Thank you for choosing us. hope to serve you better next time.

USER: Thank you.