So much for trying something different in a sitcom: The NBC comedy ”Watching Ellie” starring Julia Louis-Dreyfus will abandon its real-time element (buh-bye, ticking clock!) and single-camera format and become a traditional four-camera show with a studio audience when it returns for a nine-episode run in March. Louis-Dreyfus says she’s fine with changing ”Ellie” — the brainchild of her writer husband Brad Hall (”The Single Guy”) — primarily because she missed the type of experience she had on ”Seinfeld.” ”Getting a reaction from an audience, that’s a hard thing to give up,” she admits. ”As much fun as shooting a single-camera comedy was, you exist very much in a vacuum.” Speaking of sucking, Ellie’s life as a single L.A. lounge singer won’t get much better next season (”there will be a lot of humiliation,” she promises). Though more viewers watched ”Ellie” last season (10 million) than the critically acclaimed ”Alias” (9.7 million) and that other real-time series, ”24” (8.6 million), there are no guarantees that the changes will ensure a pickup for fall 2003. Louis-Dreyfus isn’t stressing. ”I feel much more relaxed,” she says about the show’s second outing. ”Our goal is to simply entertain.” We’ll hold her to that.