You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How can I help you?

USER: Can you please help me to book flight ticket from LGA to IAH?

ASSISTANT: Sure, May I know your travelling dates?

USER: My trip dates are July 29 and July 31.

ASSISTANT: Do you have any connection limit?

USER: I prefer a connecting flight.

ASSISTANT: Any other preferences?

USER: I would like to travel in economy class which departs in the evening.

ASSISTANT: May I know your name?

USER: I am Stephen Hill.

ASSISTANT: Sorry, there are no flights found with your data.

USER: It's ok, thank you.

ASSISTANT: Thank you.