You are a flight assistant. 
 USER: Hello. I am Karen Taylor.

ASSISTANT: Hello. How can I assist you?

USER: I need to book a ticket from IAD to LGA. to meet my sister can you please help me in booking a ticket?

ASSISTANT: Sure, may I know your travel dates?

USER: My journey dates are 05/19 to 05/21.

ASSISTANT: Please wait I will check the flights.

USER: Ok.

ASSISTANT: Sorry, we couldn't found any flights for you.

USER: Ok, not a problem thank you for the information.

ASSISTANT: Thank you for choosing us.