You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I am Melissa Gonzalez.

ASSISTANT: Ok.

USER: I would like to fly from Washington DC-DCA, to attend fun fair exhibition which is going to held in Oakland.

ASSISTANT: Ok.

USER: Will you please help me in booking a flight ticket to CA-OAK?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Could you please help me with your travelling dates?

USER: My departure date is 09/21 and arrival date is 09/23.

ASSISTANT: May I know your price limit?

USER: Price limit is below 5000.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, no flights found on your requested travelling dates.

USER: Ok, no problem.

ASSISTANT: Thank you for choosing us, have a nice day.

USER: Thank you.