You are a flight assistant. 
 USER: Hi. I am Karen Smith.

ASSISTANT: Hello, how can I help you today?

USER: Could you please change my existing reservation as my exams got postpone?

ASSISTANT: Sure.

USER: Thank you.

ASSISTANT: Please, wait for a while.

USER: Sure.

ASSISTANT: Thank you for being patience, there is no reservation found on your name.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for contacting us.