As familiar shows undergo major changes, it can be useful to look again at the episodes that set up the changes.

Usually, the previous season's finales offer the biggest clues to what's to come. Two such stories are airing again within days of each other.

On Sunday, Sept. 14, ABC's "The Practice" repeats the tale in which attorney Bobby Donnell (Dylan McDermott) leaves the Boston law firm he founded. He didn't know it when he filmed the episode, but it would be McDermott's last one as a series regular -- with co-stars Kelli Williams, Lisa Gay Hamilton, Lara Flynn Boyle and Marla Sokoloff also pink-slipped by executive producer David E. Kelley after some of them had appeared at ABC's fall-season presentation for advertisers in New York. (McDermott will return for four guest appearances in the show's new season.)

Then on Wednesday, Sept. 17, "The West Wing" reruns its fourth-season finale on NBC. The White House drama will continue to bear the phrase "Created by Aaron Sorkin" in its opening credits, but the repeat is the final story actually to have Sorkin's direct imprint. Last spring, the Emmy-winning writer-producer parted company with Warner Bros. Television, which had cautioned him to improve production practices that often included late delivery of scripts.

The 2002-03 "West Wing" finale portends other changes. With his younger daughter in the hands of kidnappers, President Bartlet (Martin Sheen) temporarily turns the Oval Office over to the speaker of the house (guest star John Goodman) in the hour's final moments. The vice president (formerly played by Tim Matheson) isn't able to step up, since he resigned after being caught in an indiscretion. The need for a new v.p. exists, and a Colorado congressman, played by Gary Cole and nicknamed "Bingo Bob," will occupy that spot as of the new season's third episode.

"The West Wing" was so much Sorkin's child, especially with its sophisticated, often rapid-fire dialogue, devotees have to wonder how others' creative input may affect it. Admittedly, new behind-the-scenes chief John Wells ("ER," "Third Watch") also has been aboard as an executive producer from the start, and he obviously knows how to make successful series.

"I don't think there's a huge change in the show," NBC Entertainment chief Jeff Zucker maintains. "Nobody was better at banter than Aaron Sorkin, but I think what John has brought to the first two scripts is some incredible character development. Where you may miss a little of the small talk in the hallway, you're going to be quite taken with how gut-wrenching and emotional this is. That's the hallmark of a John Wells show."

The hallmark of a David E. Kelley show, meanwhile, is the unexpected. He didn't disappoint in May when he caught viewers of "The Practice," as well as the dismissed actors, by surprise. Lara Flynn Boyle did little to disguise her disappointment publicly, but Kelley stresses ABC's edict to make the seven-season-old show for less money forced his move. "The task at hand," he says, "was to make the show new and fresh, so losing people and gaining people [was necessary]. The ultimate task, which was the most difficult for me, was deciding who goes and who stays."

After reprieving cast members Camryn Manheim, Michael Badalucco, Steve Harris and Jessica Capshaw, Kelley has added some big names in a bid to bolster "The Practice" (particularly since it's up against another law drama, Rob Lowe's much-ballyhooed new NBC show "The Lyon's Den"). James Spader will be a regular as a lawyer facing constant ethical dilemmas -- not unlike his "Practice" predecessor Bobby -- and Sharon Stone and Chris O'Donnell have signed up for multiple-episode guest roles. Rhona Mitra ("The Life of David Gale") also is joining the cast as a paralegal.

Kelley admits that returning to "The Practice" with only half of the original cast has been "like going to a family gathering where certain members of the family are not there. I think we're all still absorbing that. ABC was not out to punish us, I don't think. They were trying to make their best schedule, and they didn't know whether we factored into that schedule. They finally, fortunately, figured that we did."

Emmy-winning "Practice" co-star Manheim concedes that she has found it "heartbreaking" to be separated from actors she had worked with since the show's 1997 premiere. "There are two things at work here. I love my job and I want the very best for the show, and I'm going to miss Kelli's kids in the hallway and Lisa Gay's advice on moral dilemmas. There's sadness that they're not there to play with, but I'm also really excited about giving the public a new 'Practice.'"