You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I help you?

USER: My name is Charles Gonzalez. I want to do some changes in my existing reservation. Can you help me for that?

ASSISTANT: Sure, Please wait a second.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry, No reservation found on your name.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for reaching us.

USER: Welcome.