You are a flight assistant. 
 USER: Hello, I am Larry Wilson.

ASSISTANT: Hello, how may I serve you today?

USER: Owing an emergence, I want to change my existing reservation. Can you help me with it?

ASSISTANT: Sure, I will check the availability with your name to change it.

USER: Ok.

ASSISTANT: Unfortunately, We found no reservation with your specified name. Thank you for choosing us, Have a nice day.

USER: Ok, no issues. Thank you.