You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I already book a flight ticket to Oakland to attend family meeting but my meeting is postponed. Can you change my reservation?

ASSISTANT: Sure, we are here to help you. May I know your name?

USER: My name is Donald Martin.

ASSISTANT: Please wait a moment I will check the reservation and get back to you.

USER: Sure.

ASSISTANT: Sorry to say, no reservation found with your name.

USER: OK, thank you for the information.

ASSISTANT: Thanks for reaching us.