You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist today?

USER: Please help me to book a flight ticket from ATL to LGA.

ASSISTANT: Sure, may I know your travel dates?

USER: My travel dates are from May, 11 to May, 13.

ASSISTANT: Please share me your name.

USER: Mary Harris.

ASSISTANT: Sorry Mary Harris, there is no flight available at this moment.

USER: Thank you for your information.

ASSISTANT: Thank so much for choosing us.