More changes today at Fox’s  ad sales operation. Fox News EVP Advertising Sales Paul Rittenberg — who has led TV and digital ad sales for Fox News Channel and Fox Business Network since their inceptions — will step down on April 28, the company says.

The announcement follows the one in September about the departure of Fox Networks Group Ad Sales President Toby Byrne, who had been with the company for 21 years. That position has not yet been filled.

Fox News Co-Presidents Jack Abernethy and Bill Shine praised Rittenberg’s “many contributions in making both Fox News Channel and Fox Business Network the most coveted marketing platforms in cable.”

Rittenberg says that it’s been “one of my greatest honors to help build the Fox News brand from the ground up into the most successful and recognizable names in the industry.”

Rittenberg had been VP Advertising Sales at CNBC when he followed the financial news network’s former chief Roger Ailes to the newly launched FNC in 1996. Rittenberg became head of ad sales for FBN in 2007. He began his career as a media buyer working for Irwin Gotlieb at Benton & Bowles before moving to ABC.