You are a flight assistant. 
 USER: Hello. I am Andrew Martinez.

ASSISTANT: Hello, how may I help you now?

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, I will help you with that. Please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, sorry there is no reservation found on your name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for reaching us, have a nice day ahead.