War, above, and REO Speedwagon, below left, hit Reno-Tahoe this week. REO Speedwagon plays the Silver Legacy in Reno on Friday; War plays Harrah's Tahoe on Saturday. Top: Avenune Records; bottom, Witchita EagleOld rock bands rarely die. They simply transform themselves, replace players and go on nostalgia tours, frequently with other old rock bands. Northern Nevada has had more than its share of such concerts for example, teaming REO Speedwagon with Styx, with Journey, with War; or the recent blockbuster Journey with Heart and Cheap Trick. A couple of weekends from now, however, offers a chance to hear two of these legendary bands separately, allowing a more complete immersion into their music.