You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

USER: I need to change my existing reservation due to owing an emergency.

ASSISTANT: Ok, May I know your name?

USER: I am John Roberts.

ASSISTANT: Ok. We found a reservation, Can you share me your travelling details?

USER: I want to depart on 04/18 and return on 04/20. I would like to start from Charlotte, NC - CLT and return from Dallas & Fort Worth, TX - DFW. I need one connection. Price should be under 500.

ASSISTANT: Ok, Wait a minute.

USER: Sure.

ASSISTANT: There is no flight found with your details.

USER: Ok, I will find another option.

ASSISTANT: Ok, Thanks for choosing us.

USER: Thanks for your response.