Freeman’s, the venerable Center City auction house, is putting its longtime headquarters building up for sale as it plans a move to a yet-to-be identified home better suited to reaching the global pool of buyers it has increasingly come to target.

Freeman’s will begin marketing the 1924 Samuel T. Freeman Auction Co. building, at 1808 Chestnut St. near Rittenhouse Square, it said in an advance copy of a release scheduled for wide distribution Monday.

The 214-year-old auction house is leaving the six-story, neoclassical headquarters building so it can move into "one of Center City Philadelphia’s most exciting landmark buildings,” it said.

Details about the new location, which will be equipped with technology to make online auctions accessible to local, national and international buyers, will be released in the coming months, Freeman’s said.

“We are overhauling our operational and marketing systems to deliver enhanced experience and service to our clients, whether they are close to our home in Philadelphia, across the United States, or around the world," Freeman’s chairman Alasdair Nichol, who appears regularly on public television’s Antiques Roadshow, said in the release.

Founded in 1805, Freeman’s bills itself as the oldest auction house in the United States. One memorable lot included a broadside version of the Declaration of Independence that sold for more than $400,000 after it was found among the inventory of Leary’s Book Store when the Philadelphia bookseller closed in the late 1960s.

Major sales in recent years have included artworks from the New York, Boston and Delaware offices of the defunct investment bank Lehman Bros., among which were prints by pop artist Roy Lichtenstein and LOVE statue designer Robert Indiana.

Freeman’s planned move comes about three years after a consortium of auction industry veterans involving Nichol acquired the business, including its headquarters building, from its namesake family.

Before buying Freeman’s, the ownership group had worked for the auction house, reshaping the business to target a geographically far-flung segment of wealthy buyers with carefully curated inventory. That represented a shift from its previous strategy of selling large lots of art and antiques from nearby estates to local buyers.

The move is part of Freeman’s increasingly internationally minded approach, Nichol said in the release.

“We recognize our clients’ expectations are changing,” he said. “Our private and institutional buyers and sellers come from every continent, and we must be fully equipped to meet their expectations.”

Freeman’s has retained brokerage MPN Realty Inc. to market its longtime headquarters.