You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I want to change my reservation, due to some problems I am unable to travel those dates, can you please change my reservation?

ASSISTANT: Sure, may I know your name?

USER: Sure, my name is Christine Williams.

ASSISTANT: There is no previous reservation found under your name.

USER: Oh! It's ok no problem, thank you for your information.

ASSISTANT: Most welcome.