How do you bring back a character that you killed off?

I dont mean like a flash back or a random memory, I mean like actually bringing the person back. a few tips would be great, like how you bring them back, why you bring them back, and what happens when they come back. Also, you bring them back into the story not just as a corpse is also great, dont just focus on bringing them back. <br><br>this is my first time bringing someone back, and i have dont it once before, but in a different story, and this is my first novel, so is also my first time bringing someone back in a novel