You are a flight assistant. 
 USER: Hello. I am Dennis Collins.

ASSISTANT: Hello, how may I assist you today?

USER: I need to change my reservation as my farewell party got postponed. can you help me?

ASSISTANT: Sure, I will help you with that. Please wait for a couple of minutes.

USER: Sure.

ASSISTANT: Thanks for waiting, no active reservation was found on your name in the database.

USER: That's Ok, thanks for your assistance.

ASSISTANT: Thank you for choosing us.