Demolition has started on the lobby of 550 Madison Avenue, the Philip Johnson-designed office building that’s heralded as the most iconic postmodern structure in New York City. The lobby remodel is part of building owners’ Olayan America and Chesfield America’s plan to modernize the former Sony and AT&T headquarters with an overhaul by architecture firm Snøhetta.

The remodel was announced in late October and instantly provoked a campaign by preservationists who sought to secure landmark status for the building’s monumental stone facade and lobby. The Landmarks Preservation Commission calendared the building’s exterior for designation, but decided its lobby was not worth preserving in its current state, citing a 1993 Gwathmey Siegel Kaufman renovation that significantly altered it from its original design.

The Architect’s Newspaper, who first reported the interior demolition, says that scaffolding is in place in the lobby and its windows are now papered over. Thomas Collins, the architecture buff who initially submitted the Request for Evaluation for landmark status with LPC in late October, spotted the sure signs of construction.

“It’s not clear why they’re rushing forward at this stage,” Collins told AN. “I believe they are primarily gutting the lobby for aesthetic and marketing purposes.”

Papered over windows and eight security guards inside and out. pic.twitter.com/s807w90GAT — Docomomo US (@docomomo_us) January 9, 2018

“The LPC made this decision behind closed doors—they knew they were going to rip out the interior,” Liz Waytkus, executive director of Docomomo US, said to AN. “I feel like it’s a bait-and-switch.”

However, building co-owner Chelsfield America has expressed its support for the LPC’s decision to consider 550 Madison Avenue for exterior landmark status. “We have received both praise and critical commentary on the design and we are committed to developing a thoughtful approach,” David Laurie, the managing director of Chelsfield America , said in a statement issued to Curbed in late November. “We recognize that the building has broad appeal and is at various levels an important part of architectural heritage, so we value a constructive dialogue as we develop the plans further.”