You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you today?

USER: Due to sudden change in my trip to another location, I would like to do some changes in existing my reservation. Can you please help me out?

ASSISTANT: Sure, may I know your name for the changing process?

USER: My name is William Phillips.

ASSISTANT: Thank you, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, we couldn't find a reservation on your name to change.

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

ASSISTANT: Welcome, thank you for reaching us.