You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I support you today?

USER: I am Jacob Smith. I want to change an existing reservation due to sudden change in my trip. Can you help me with this?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Thanks for waiting, no reservation found with your name to change.

USER: No issue. Thank you.

ASSISTANT: Thanks for approaching us.