You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I want to do some changes in my existing reservation. can you help me for that?

ASSISTANT: Sure, I am here to help you. May I know your name please?

USER: My name is Daniel Gonzalez.

ASSISTANT: Ok, please wait for a moment.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry Daniel, there is no reservation found as per your name to change your reservation in your database.

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

ASSISTANT: You are welcome.