Ambassador Theater Group, the largest theater owner-operator in the U.K. and a company in the midst of expanding its New York footprint, has tapped new leadership as its founding leaders and co-CEOs, Howard Panter and Rosemary Squire, step down from their current posts to focus on theater production.

Mark Cornell, the former managing director of Sotheby’s Europe and a veteran of LVMH, will join the company as Group Chief Executive Office, while Adam Kenwright, a co-founder of the theater marketing and communications firm AKA, has been tapped to serve as executive vice president of ATG.

Husband-and-wife team Panter and Squire, meanwhile, are purchasing London’s Trafalgar Studios Theater from ATG, with the intention of establishing a new creative direction for the venue where director Jamie Lloyd and ATG launched buzzy programming including “Macbeth” with James McAvoy and the current “Doctor Faustus” with Kit Harrington.

ATG, which has made no secret of its expansive international ambitions, purchased Broadway’s Lyric Theater (then called the Foxwoods) in 2013, and late last year announced plans to renovate the Hudson Theater into a new Broadway venue. Last year ATG also acquired Brooklyn’s Kings Theater.

Given Cornell’s experience with global brands, it’s expected that ATG will continue its international expansion, including its growth in the U.S. (Being a theater landlord is one of the surest routes to profit in the theater business, since even flops pay rent.)

Both Panter and Squire will remain affiliated with ATG, with Panter continuing his role as executive producer on some current and future theater productions. He’ll also continue to serve as chairman and producer of “The Rocky Horror Show.” Squire, meanwhile, will become deputy chair of ATG Group, and retain her role as chair of Sonia Friedman Prods. (“Harry Potter and the Cursed Child”), the ATG subsidiary that is a major player on both Broadway and the West End.

Providence Equity Partners acquired a majority stake in ATG in 2013, and has since invested some £130 million ($190 million) in the company.  ATG owns about 45 theater venues in the U.K., the U.S. and Australia, and also owns a number of British ticketing services including ATG Tickets and Group Line.