You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Frank Smith. I want to chnge my reservation, due to some health issue. Can you please help me out?

ASSISTANT: Sure, please wait for a while.

USER: Ok, take your time.

ASSISTANT: Sorry Smith, there is no active reservation found with your name in our records.

USER: That's ok, thank you for checking.

ASSISTANT: My pleasure.