You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I am Andrew Baker. I need to change my existing reservation, as my exam got postponed. Please help me in changing?

ASSISTANT: Sure, please wait a moment.

USER: Ok.

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

USER: Ok, no issues. Thank you.

ASSISTANT: Thanks for reaching us.