A changing of the guard is afoot at two Am Law 200 firms.

Phoenix-based Snell & Wilmer announced on Tuesday that John Bouma, who served as chair for 30 years, will be replaced by corporate partner Matthew Feeney on March 1. Columbus, Ohio-based Porter Wright Morris & Arthur revealed its own leadership change that same day, with its chief operating partner Robert Tannous to take over on Jan. 1 for Robert “Buzz” Trafford, who served managing partner for 18 years.