You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I guide you for today?

USER: I would like to prefer a flight with lay-by option for my business trip to Houston. Can you book the flight ticket?

ASSISTANT: Can you please share on what dates you are willing to travel?

USER: The trip dates are from 24 June to 26 June.

ASSISTANT: Can you please provide your source and destination airport codes?

USER: The airport codes are from LGA to IAH.

ASSISTANT: Do you have any class preferences?

USER: No.

ASSISTANT: Do you have any other requirements that you are looking for?

USER: That is it.

ASSISTANT: Can you please provide your name to proceed further?

USER: I am Nicholas Taylor.

ASSISTANT: Sorry, there are no flights available at your request.

USER: Not a problem. Thank you.

ASSISTANT: Thank you for contacting us, have a nice day.