You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I made a reservation earlier on wrong dates unknowingly. So, I want to change my existing reservation. Can you please help me?

ASSISTANT: Please let me know your name.

USER: My name is Jennifer Lewis.

ASSISTANT: Reservation found. Please provide your travelling codes.

USER: My airport codes are DFW and EWR.

ASSISTANT: May I know your travel dates?

USER: I would like to depart on 12/03 and return on 12/05.

ASSISTANT: Any specifications?

USER: I need a lay by. Price should not exceed 1000.

ASSISTANT: No flights found with your requirement.

USER: Ok, no issue.

ASSISTANT: Thanks.

USER: Thanks for your help.