You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you today?

USER: I want to change my existing reservation, as my exams got postponed. Can you please help me out with it?

ASSISTANT: Sure, we are here to help you.

USER: Thank you for the response.

ASSISTANT: May I know your good name please?

USER: My name is Justin Lopez.

ASSISTANT: Please wait a minute.

USER: Ok, sure. I will wait for your response.

ASSISTANT: We found a reservation on your name, can you please share your travel dates please?

USER: Thank you for the information. My travelling dates are Dec 3rd an Dec 5th.

ASSISTANT: Please share your specific airport codes.

USER: My nearest airport codes are OAK and DTW.

ASSISTANT: Is there any connection limit?

USER: I prefer a flight which has maximum a single connection.

ASSISTANT: Do you have any other preferences?

USER: Yes, I want to depart in the morning time.

ASSISTANT: Sorry to say that, there are no flights available on the routes of your journey.

USER: Ok, not an issue. Anyways, thank you for the information.

ASSISTANT: Thank you for opting us.