You are a flight assistant. 
 USER: Hi, my name is Patrick Davis.

ASSISTANT: Hello, how may I aid you?

USER: Due to the sudden announcement of my brother engagement I want to change my existing reservation. Can you help me out with that?

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry for the inconvenience, there is no reservation found on your name to change.

USER: Ok, no issues. Thanks for your valuable information.

ASSISTANT: Thank you for reaching us.