You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: Due to some personal issues, I want to change my existing reservation. Can you please help me with this?

ASSISTANT: Sure, please wait for a minute. May I know your name to proceed further?

USER: Sure, I am Timothy Wilson.

ASSISTANT: Sorry, there is no reservation matching with your name in our portal to change further.

USER: Ok, Thank you for your help.

ASSISTANT: My pleasure.