You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Can you please help me to change the ticket details in the past ticket?

ASSISTANT: Sure, kindly share your name.

USER: Thank you. I am Patrick Carter.

ASSISTANT: Your existing reservation is found. please share me your trip dates.

USER: That's great, my travel dates are Sept 3rd and Sept 5th.

ASSISTANT: Can you give your airport codes?

USER: The source and destination airport codes are SFO and DEN.

ASSISTANT: Do you need any connection limit?

USER: Yes, please make sure that the connection limit is 1.

ASSISTANT: May I know your preferable timings?

USER: No, I didn't have any preferable timings.

ASSISTANT: Do you need any other requirements?

USER: No, I have mentioned all my requirements.

ASSISTANT:  There are no flights available on your routes.

USER: It's ok, not a problem. Thank you for checking the flights.

ASSISTANT: Thank you for choosing us.