Brake pad warning light

[imperial-custom]

Hi all. My brake pad warning light has come on. I will be changing both discs and pads as both are low. When I have changed them, will the light go out automatically or will it need to be reset? Do I need to replace any sensors? Car is a 51 plate 2.0 8v petrol AZM engine 115BHP.

Thanks in advance.

Ray.