You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Linda Lewis.

ASSISTANT: Lewis, how may I assist you?

USER: I planned to attend for a meeting in DFW, can you please help me to book a flight ticket from LGA?

ASSISTANT: Sure, I will help you. Can you please let me know your travel dates?

USER: I prefer to travel on 07/25 and 07/27.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform you that there is no flight available on your preferred travel dates.

USER: Ok, no problem. Thank you for your time.

ASSISTANT: You are welcome and thank you for choosing us.