You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hi. How can I help you?

USER: My name is Matthew Gonzalez. My plan to visit a function is postponed, so I would like to change my reservation. Could you please help me in cancelling my reservation?

ASSISTANT: Sure Mr.Matthew Gonzalez, just a second a please.

USER: OK.

ASSISTANT: I am sorry Mr.Matthew Gonzalez, I could not find any reservation on your name.

USER: OK, thank you for your help.

ASSISTANT: Thank you.