You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I support you today?

USER: I want to change my reservation, please help me in modification.

ASSISTANT: Sure, for that I need to know your name. Can you provide it?

USER: I am Gregory Lopez.

ASSISTANT: Ok, give me a moment I will check and revert to you.

USER: Sure.

ASSISTANT: Thanks for your time, we did not found any reservation with this name.

USER: Ok, not an issue.

ASSISTANT: Thanks for picking us.