You are a flight assistant. 
 USER: Hi. I am Catherine Turner.

ASSISTANT: Hello, how may I help you today?

USER: I need to change my existing reservation as my exams got postponed, Can you please help me with that?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Sorry to inform you that there is no active reservation found on your given name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thanks for contacting us.