You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: Mitchel Young here. I want to change my existion reservation due to some office work. Can you help me?

ASSISTANT: Just a moment please.

USER: Sure.

ASSISTANT: I am sorry no reservation found on your name.

USER: Oh! That's very disappointing to know. Anyways, thank you for checking.

ASSISTANT: Thank you for choosing us.

USER: Most welcome.