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

ASSISTANT: Hello, how can I help you today?

USER: I need to change my existing reservation as my examinations got postponed. Can you help me with that?

ASSISTANT: Sure, please wait a moment.

USER: Ok.

ASSISTANT: Sorry to say, no reservation found with your name.

USER: That's ok, thank you for the information.

ASSISTANT: Thanks for reaching us, have a good day.