You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you today?

USER: my name is Larry Hernandez. I want to change my existing reservation as my art gallery expo got postponed. Can you help me in change in reservation?

ASSISTANT: Sure. Please wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found on your name.

USER: Ok, No problem. Thank you.

ASSISTANT: Thank you for choosing us.