You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: My name is Charles Lopez. I just need your help in changing my existing reservation details.

ASSISTANT: Sure, please give me a minute.

USER: Ok.

ASSISTANT: There is no reservation found with your details, Charles.

USER: That's ok, thank you for the information.

ASSISTANT: Thank you for your assistance.