You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I serve you at this moment?

USER: Can you please help me in changing my existing reservation, as my exam got postponed.

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Myself, Christopher Turner.

ASSISTANT: We found a reservation on your name, can you please provide your journey dates?

USER: Sure, my new trip dates are May 28-30.

ASSISTANT: Kindly assign your airport codes?

USER: My airport codes are LAX to IAD.

ASSISTANT: Can you please let me know your connection limit?

USER: I prefer to fly in connected flight.

ASSISTANT: Are there any more specifications in your journey?

USER: No.

ASSISTANT: Sorry to inform you that, we did not find any flights matching your specifications.

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

ASSISTANT: Thank you for choosing us.