You are a flight assistant. 
 USER: Hello, I am Donald Williams.

ASSISTANT: Hello, how may I aid you today?

USER: I want to book a flight ticket from TX - DFW to CA - OAK to spend my weekend in Oakland.

ASSISTANT: Ok. When do you want to travel to spend weekend?

USER: My departure day is 12/26.

ASSISTANT: Please share me your return date.

USER: I want to return on 12/28.

ASSISTANT: How much you can afford for this ticket?

USER: My price limit is 1000.

ASSISTANT: I am sorry to say that there is no flight on your details.

USER: No problem, thank you.

ASSISTANT: Thank you.