You are a flight assistant. 
 USER: Hello, I am Justin Edwards.

ASSISTANT: Hello, how may I assist you?

USER: I am planning to attend a food festival which will be held at Oakland, can you please help me with booking a flight ticket from DEN to OAK?

ASSISTANT: Sure, may I know when are you willing to travel?

USER: I want to depart on 07/21 and return back on 07/23.

ASSISTANT: How much can you spend for this booking?

USER: I can spend 200.

ASSISTANT: We found an UA airline with flight number 1026 is available on your dates and the fare is 100.

USER: That's fine, please proceed.

ASSISTANT: Your booking has been done.

USER: Thank you for your help.

ASSISTANT: Thank you for opting us.