You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I guide you?

USER: I want to change my reservation due to health issues, can you help me with this?

ASSISTANT: Sure, may I know your name?

USER: Myself David Perez.

ASSISTANT: We have found your reservation, can you share your trip dates?

USER: My trip dates are Dec 16 and Dec 18.

ASSISTANT: May I know your airport codes?

USER: My airport codes are from DTW to SEA.

ASSISTANT: Do you have any preferences?

USER: I prefer a stopover in between my journey.

ASSISTANT: There is a connecting flight with number 1018 in airline UA, the fare is 200 in economy class. Can I book it?

USER: Yes, you can book it.

ASSISTANT: Your ticket is reserved, the depart time is 17:00 and return time is 14:00.

USER: Ok, thank you for booking.

ASSISTANT: Thank you for choosing us.