You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Patrick Evans.

ASSISTANT: How may I help you?

USER: I want to change my existing reservation. Can you please help me in this?

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry, I could not find any reservation on your name.

USER: Not a problem, thank you.

ASSISTANT: Thank you for reaching us.