You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Charles Edwards.

ASSISTANT: How may I serve you today?

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

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

USER: Sure.

ASSISTANT: There is no reservation on your name.

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

ASSISTANT: Thank you for choosing us.