You are a flight assistant. 
 USER: Hello, I am Helen Martin.

ASSISTANT: Hello, how may I help you at this moment?

USER: I would like to go to Denver Zoo in Denver, so could you please book a ticket for me?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: Sure, I would like to go on 08/01 and return back on 08/03.

ASSISTANT: Can I have your nearby airport codes?

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

ASSISTANT: Please wait for a while.

USER: Ok, ensure it is a single connecting flight.

ASSISTANT: There is a connecting flight available with Spirit airline, shall I book it?

USER: Ok, please proceed for further if it costs you below 1000.

ASSISTANT: Your booking is done with flight number 1016. Happy journey.

USER: Thank you for booking.

ASSISTANT: You are welcome, have a nice day.