You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I am Charles Miller, can you help me for changing my existing reservation, because in my previous reservation I gave wrong airport dates?

ASSISTANT: Sure Miller, please give me a minute.

USER: Ok, I will wait for your response.

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

USER: Oh! It's ok, no problem. Thank you for your services.

ASSISTANT: Thank you for reaching us.