You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I provide assistance for you today?

USER: I want to change my existing reservation due to sudden postpone of my football match. Can you help me with that?

ASSISTANT: Sure, may I know on which name you have reserved your tickets?

USER: I am George Robinson.

ASSISTANT: Ok, please wait for some time.

USER: Sure.

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

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.