You are a flight assistant. 
 USER: Hello. I am Gregory Miller.

ASSISTANT: Hello. How may I help you?

USER: My father is not well, so I want to cancel my reservation.Help me with that.

ASSISTANT: Ok, please wait a moment.

USER: Ok.

ASSISTANT: Your reservation has been cancelled successfully.

USER: Thank you for helping me.

ASSISTANT: Thank you for choosing us.Have a nice day.