Post-production vet Robert Walston is stepping down as prexy and CEO of Liberty Livewire, the conglom of post facilities owned by media mogul John Malone. He is being replaced by William Fitzgerald, who assumes the role of acting CEO until a new topper is found.

Walston founded and was chairman and CEO of post-production facility Four Media before it was bought out by Liberty Media and joined the conglom’s new Liberty Livewire group in 2000.

He is ankling to pursue other opportunities.

Fitzgerald has been Liberty Livewire chairman since 2000 and will now expand his involvement in the company’s daily operations. He also serves as senior VP of Livewire parent Liberty Media. Before joining Liberty, Fitzgerald was exec VP and chief operating officer for AT&T Broadband.

Over the past two years, Liberty Media has spent millions to buy up roughly 50 small and large post-production facilities, including Four Media Co., Todd-AO, Soundelux, Hollywood Digital and Riot, and consolidate them all under one roof called Liberty Livewire.

Through Four Media, Walston had been doing the same, acquiring and integrating 28 companies, such as Company 3, Digital Sound and Picture and Encore Video, under the company’s umbrella.

Taking a break from its shopping spree, Liberty Livewire is now looking to boost its image and service offerings to film, television and commercial producers.