You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: Please help me to book a flight ticket from LGA to IAD?

ASSISTANT: May I know your planned dates to travel?

USER: My travelling dates are Apr 18 to Apr 20.

ASSISTANT: Is there any connection limit?

USER: I need a single connection of flight.

ASSISTANT: May I know your good name?

USER: William Jackson here.

ASSISTANT: Do you have any other requirements?

USER: No.

ASSISTANT: Sorry, there were no flights found with your required dates to travel.

USER: It's ok, thank you.

ASSISTANT: Thank you for choosing us.