You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you today?

USER: I got a race to participate, for practising the race I need to go, but he race was postponed.

ASSISTANT: OK.

USER: So, please change my existing reservation.

ASSISTANT: Sure, I will help you with that but I need your name to check the reservation details.

USER: I am Paul Walker.

ASSISTANT: Sorry, I could not find any reservation with your name.

USER: Ok. Thank you.

ASSISTANT: It's my pleasure.