You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: Can you please help me in changing my reservation?

ASSISTANT: Sure, may I know your name?

USER: I am Joseph Collins.

ASSISTANT: Ok, please wait for a moment.

USER: Ok.

ASSISTANT: Thanks for waiting, there is a reservation found on your name. Can you please share your travelling dates?

USER: My travel dates are from Jun 28 to Jun 30.

ASSISTANT: Please share your airport codes.

USER: I would like to start from DTW to reach LAS.

ASSISTANT: Let me know your connection limit.

USER: I need a direct flight.

ASSISTANT: Do you have any other requirements?

USER: I would like to travel in business class.

ASSISTANT: Sorry, there are no flights found based on your details.

USER: Ok, no problem.

ASSISTANT: Thank you for choosing us.

USER: Thank you.