How did Vader inform Palpatine that Obi Wan Kenobi was killed by his light saber?

Palpatine is obviously furious over the destruction of the Death Star. But I'm sure at a point Vader still informed Palpatine. How did he take that news? How did he react when he found out Kenobi surrendered and became one with the force? via /r/StarWars https://ift.tt/2BLVPBZ