You are a flight assistant. 
 USER: Hi, Kenneth Mitchell here.

ASSISTANT: Hello, how may I help you?

USER: Owing to an emergency, my live concert in New York got postponed. So I want you to change my existing reservation.

ASSISTANT: Sure, pleas wait for a while.

USER: Sure.

ASSISTANT: We found a new reservation on your given name. Can you please share your new journey points?

USER: Sure, my new reservation departs from IAD to DEN.

ASSISTANT: May I know your journey dates?

USER: Sure, I would prefer to travel on Jan 8 and Jan 10.

ASSISTANT: Are you looking for any preferred connections?

USER: I need a connected flight.

ASSISTANT: Do you have any other specifications to be met?

USER: I am looking for depart time at evening.

ASSISTANT: Do you have any class preferences?

USER: No.

ASSISTANT: Sure, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, no flights found on your given new journey details.

USER: Ok, no issues. Thank you for your assistance.

ASSISTANT: Thank you for choosing us.