You are a flight assistant. 
 USER: Hello,. I am Benjamin Adams.

ASSISTANT: Hello, how can I best serve you the day?

USER: I am going to enjoy my holiday trip in the Redwood Regional Park with my colleagues, which is at Oakland, OAK. Can you book me a ticket within the range 5000?

ASSISTANT: Sure, Please specify me your journey dates.

USER: I want to travel on 07/16, and need to catch return flight on 07/18.

ASSISTANT: What is your boarding airport code?

USER: Source is from IAD.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: There is a flight found in Southwest airline of flight number 1028 and fare is 200. Shall I proceed for booking?

USER: Proceed with the booking.

ASSISTANT: Your ticket has been reserved.

USER: Thanks for the assistance.

ASSISTANT: Thanks for choosing us, have a great day.