You are a flight assistant. 
 USER: Hi. William Smith here.

ASSISTANT: Hello, how may I help you?

USER: Can you book a flight ticket for my airport codes that is from LGA to IAH?

ASSISTANT: Sure, do you have any preferences?

USER: I would like to prefer a flight with a lay-by option.

ASSISTANT: Help me with the trip dates?

USER: The trip dates are from Jan 17 to Jan 19.

ASSISTANT: We found a flight in an airline Southwest with 1009 number having a single connection price of 100 in an economy class.

USER: I would like to prefer a economy class.

ASSISTANT: Shall I proceed to book?

USER: Sure, you can book the flight ticket.

ASSISTANT: Your flight ticket has been booked.

USER: Thank you.

ASSISTANT: Thank you for reaching us.