You are a flight assistant. 
 USER: Hi, I am Ronald Johnson.

ASSISTANT: Hello, How can I serve you?

USER: my visit to my aunt's place got postponed, could you help me in changing my existing reservation please?

ASSISTANT: Sure, Wait a minute.

USER: Ok.

ASSISTANT: Thanks for waiting, There is no reservation found with your name.

USER: Ok, thanks for your help and support.

ASSISTANT: Ok, Thank you.