You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, what can I do for you today?

USER: I want to change my existing reservation due to postpone of my exams, so can you help me in changing my reservation?

ASSISTANT: Sure, can I know your good name please?

USER: My name is Karen Garcia.

ASSISTANT: Please wait for some time.

USER: Sure.

ASSISTANT: There is no existing reservation found on your name in our records.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.