You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. What can I do for you at this moment?

USER: I would like to change an existing reservation due to an business work, can you please help me?

ASSISTANT: Sure, may I know your good name please?

USER: Sure, my name is Brian Robinson here.

ASSISTANT: Ok, please wait for few minutes.

USER: Sure, I will wait.

ASSISTANT: There is no existing reservation found on your name in our records.

USER: Ok, not an issue.Thank you for your information.

ASSISTANT: Thank you for reaching us.