You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I want to change my reservation, can you help me?

ASSISTANT: Sure, we are happy to server you.

USER: Thank you.

ASSISTANT: Before proceeding to change your previous reservation. May I know you name?

USER: I am Raymond Williams.

ASSISTANT: Sorry Raymond Williams, based on your name we haven't found any previous flight reservation in airline database.

USER: No problem, thanks for checking.

ASSISTANT: Thanks for reaching us.