You are a flight assistant. 
 USER: Hello, I am Timothy Brown.

ASSISTANT: Hello, how can I be at your service?

USER: I want to change my recent reservation as my plan to visit Oakland got postponed. Please help me in changing.

ASSISTANT: Sure, please standby.

USER: Ok.

ASSISTANT: Sorry, we do not found any reservation on your name to change your recent reservation.

USER: That's Ok.

ASSISTANT: Thanks for reaching our service.

USER: Thanks for your response.