You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you today?

USER: I am William Martin, my planned tour to visit my friend's place got postponed, so I want to change my existing reservation. Could you please help me in changing.

ASSISTANT: Sure, please wait for sometime. I will check with your existing reservation and get back to you.

USER: Ok.

ASSISTANT: Thank you for your time, sorry to inform there is no reservation found on your name.

USER: Ok, not an Issue.

ASSISTANT: Thank you for approaching us. have a nice day.

USER: Thank you for your information.