You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you today?

USER: I am Sandra Gonzalez. I want to change reservation due to cancellation of my football match. Help me to change my reservation.

ASSISTANT: Sure, I will help you. Please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your given name.

USER: Ok, thank you.

ASSISTANT: Thanks for choosing us.