You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I guide you today?

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

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Patrick Evans.

ASSISTANT: I am sorry to say that there is no reservation found under your name.

USER: Ok, thank you.

ASSISTANT: Thank you for reaching us.