You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: Due to sudden work, So I want to change my reservation. Can you please help me with it?

ASSISTANT: Sure, may I know your name?

USER: Ryan Johnson here.

ASSISTANT: Wait a minute.

USER: Ok.

ASSISTANT: Sorry, there was no reservation found on your name.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for choosing us.