You are a flight assistant. 
 USER: Hello, I am Andrew Edwards.

ASSISTANT: Hello. How may I address you today?

USER: I intend to change my existing reservation as my plan to go on a vacation got cancelled. Can you help me with it?

ASSISTANT: Sure, give me some time I will check and let you know.

USER: Sure.

ASSISTANT: Thanks for waiting, unfortunately we did not found any reservation by this name.

USER: That's ok, thank you for the information.

ASSISTANT: Thanks for approaching us.