You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I am Patrick Lewis, want to travel from HOU to LGA. Please help me in booking my ticket.

ASSISTANT: Sure, I will help you with the flight ticket reservation. May I know your travel dates please?

USER: Thank you and my travelling dates are from 05/25 to 05/27.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for your time. But I am sorry to inform you that there are no flights found with your flight details.

USER: It's ok, thank you for your help.

ASSISTANT: Thank you.