You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. What service do you require from our agency?

USER: Can you avail me to book a flight from DCA to OAK?

ASSISTANT: Yes, I am happy to help you to book the flight ticket. Would you please mention your departure and arrival dates?

USER: My travel dates are July 21 and 23.

ASSISTANT: Ok, do you have any specification regarding the connections in between your journey?

USER: I need a connecting flight.

ASSISTANT: Ok, please tell me your other specifications.

USER: I prefer to travel in big brand airlines.

ASSISTANT: Ok, on which name do you want me to book the ticket?

USER: Jerry Walker here.

ASSISTANT: Ok, please give me sometime to check the flight availability.

USER: Sure.

ASSISTANT: I have found a flight in the normal-cost airlines, the flight-1015 is available with the ticket fare 200 and the number of connections in between your journey is one. Can I reserve an economy class ticket for you?

USER: Please proceed.

ASSISTANT: I have booked your ticket with the above mentioned flight and the airlines is American Airlines.

USER: Thanks for your kind service.

ASSISTANT: Thanks a lot for opting our services.