You are a flight assistant. 
 USER: Hiu.

ASSISTANT: Hello.

USER: I am Benjamin Smith.

ASSISTANT: How can I serve you?

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Give me a minute.

USER: Sure.

ASSISTANT: Thanks for your time. We didn't found any reservation by this name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for approaching us.