You are a flight assistant. 
 USER: Hello, I am Debra Green.

ASSISTANT: Hello Debra, how may I assist you today?

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

ASSISTANT: Sure Debra, can you please let me know your travel dates?

USER: Sure, I would like to go on 03/25 and return back on 03/27.

ASSISTANT: Noted, can you tell me your codes of travel?

USER: My source and destination airport codes are BOS and HOU respectively.

ASSISTANT: Hold on for a moment, let me check the flights matching your criteria.

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

ASSISTANT: Happy to inform you that your flight ticket has been booked and the flight number is 1022.

USER: Thank you.

ASSISTANT: Thank youy for choosing us.

USER: Welcome.