Cast departures and changes within the 'Law & Order' franchise are are a dime a dozen these days. So much so that most fans tend not to notice when they occur. The exception is when a long-running cast member decides to step down. Fans take notice then because, frankly, there aren't too many more long-running cast members left in the franchise (except the amazingly stable group at 'Special Victims Unit.'

This time the honor goes to S. Epatha Merkerson, who plays Lieutenant Van Buren in the original 'Law & Order'. After 16 years, the actress has decided to leave the series at the end of this season.

Sam Waterston wants a promotion. For the last 13 years Waterston has played Assistant District Attorney Jack McCoy on the long-running (some say too long) NBC drama Law & Order. Now that co-star, and former U.S. Senator, Fred Thompson (who played District Attorney Arthur Branch) is leaving the show to run for president of the United States his job position is now open. And, it seems that Waterston's McCoy wants to move into the slot.

According to an anonymous source close to the show, Waterston is negotiating to have his character step into the D.A. role when Law & Order returns at the beginning of 2008. How McCoy would slip into the position, as well as his replacement, have yet to be determined. When asked to confirm this news L&O creator Dick Wolf as well as Waterston declined to comment.