You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

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

ASSISTANT: Sure, I will help you. Can I know your good name please for further process?

USER: I am Katherine Harris.

ASSISTANT: Ok, please wait for some time.

USER: Sure.

ASSISTANT: Thank you for being patient. there is no existing reservation find on your good name.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for approaching us for changing the reservation.