You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Steven Lee here.

ASSISTANT: How could I assist you?

USER: Please help me out in booking the ticket from HOU to LAS.

ASSISTANT: Sure, I will help you in booking may I know your planned trip dates?

USER: My trip dates will be Oct 25 to Oct 27.

ASSISTANT: Do you want to fly with economy class or business class?

USER: Economy class.

ASSISTANT: Is there any airline preference for you?

USER: No.

ASSISTANT: Kindly mention your specifications?

USER: Return time must be in the evening with 1 connection.

ASSISTANT: There is no flight found with your provided information.

USER: That's ok. Thank you.

ASSISTANT: Thank you.