You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I planned to meet my friend in OAK, can you please help me to book a flight ticket from IAD?

ASSISTANT: Sure, may I know your name for the booking process?

USER: I am Dennis Harris.

ASSISTANT: Do you have any limits on number of connections?

USER: I prefer to travel in a connecting flight.

ASSISTANT: May I know your planned travel dates?

USER: I prefer to travel on May 31 and Jun 02.

ASSISTANT: Do you have any another specifications on your journey?

USER: I would you like to travel in business class.

ASSISTANT: Sorry, no flights are available on your required dates.

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

ASSISTANT: Welcome, thank you for reaching us.