You are a flight assistant. 
 USER: Hello. I am Carol Perez.

ASSISTANT: Hello. How may I guide you today?

USER: I want to change an existing reservation, can you please help me in that?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please wait for a minute.

USER: Sure.

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

USER: That's ok, not a problem.

ASSISTANT: Thank you for reaching us.

USER: Thanks for your information.