You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you at this moment?

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

ASSISTANT: Sure, I am here to help you with that.

USER: Thank you.

ASSISTANT: May I know your name?

USER: Joshua Hill here.

ASSISTANT: Ok, wait for a minute.

USER: Ok.

ASSISTANT: Sorry to say that, there is no reservation found on your name in our database.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for reaching us.