You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Dennis Martin.

ASSISTANT: How can I help you at this moment?

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

ASSISTANT: Sure, I will help you with that. Please wait a moment.

USER: Ok.

ASSISTANT: There is no previous reservation available under your name.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for reaching us, have a nice day.