You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Ronald Garcia here.

ASSISTANT: How may I help you out?

USER: I want to visit Houston to meet my family, so please book my ticket from OAK to IAH.

ASSISTANT: Sure, I will help you in booking the ticket. May I know your travelling dates please?

USER: My trip dates are Apr 18 and Apr 20.

ASSISTANT: Do you need any specifications?

USER: I want to return in the evening.

ASSISTANT: Can I know your preferences?

USER: I need a connecting flight.

ASSISTANT: Sorry, there are no flights found.

USER: No problem, thank you.

ASSISTANT: Thank you for reaching us.