You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: I am Thomas Harris. Can you help me booking a flight ticket from LGA to IAH?

ASSISTANT: Sure, may I know your travelling dates?

USER: My travel dates are from Jun 23 to Jun 25.

ASSISTANT: Do you have any other requirements?

USER: I would like to depart in the morning and return in the evening.

ASSISTANT: Can I know your class preference?

USER: No.

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

USER: No problem, thank you.

ASSISTANT: Thank you for choosing us.