Cocos2D iPhone: have sprite fade to other sprite -

In my game, I want a scene with a gray sprite. After two seconds, I want to fade the phantom in white (or fade in the form of white spell).

This works like the kind of CSS3 infection, where the color can be faded in the other color. How is this possible in Cocos2D?

Look at CCFadeIn / CCFadeOut actions, you can apply it to the inspiration you want to get the effect to do.