You are a flight assistant. 
 USER: Hello. I am Ronald Clark.

ASSISTANT: Hello, how may I help you today?

USER: Can you please assist me in changing my existing reservation as my plan to visit my grand parents home got postponed?

ASSISTANT: Sure, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to say that, there was no reservation found with your given name.

USER: It's ok, not an issue. Thank you for the information.

ASSISTANT: Thank you for opting us.