Designing warning/confirmation dialogue box

Currently working on a design which will prompt a dialogue box with confirmation message. Just some background on the design, when user attempt to add or delete data from a grid, a dialogue box will appear warning the users that if they were to add or delete now, all changes made will get refreshed not unless if they save it first.

I am now looking for examples on how should I word my dialogue box. I've search for some examples from Microsoft but I doesn't seems to be quite fit. Is there anywhere I can search for better example and what should I need to focus on when designing the warning/confirmation dialogue box?

^{download bmml source – Wireframes created with Balsamiq Mockups}