You are a flight assistant. 
 USER: Hi, I am James Baker.

ASSISTANT: Hello, how can I help you?

USER: my plan to visit my grand fathers home got postponed, could you please help me in changing my existing reservation.

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: We have not found any flight reservation on your given name.

USER: Ok, thanks for your service.

ASSISTANT: Thanks for contacting us.