You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I serve you today?

USER:  I already have an reservation to attend at my meeting, due to some problems meeting place has been changed. Can you please help me to change an existing reservation?

ASSISTANT: Sure, may I know your name please?

USER: I am Samuel Taylor.

ASSISTANT: Please wait, I will search your name in our database and revert to you.

USER: Ok.

ASSISTANT: Sorry to say that, no flights were found on the name of Samuel Taylor.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for choosing us.