The word “grand” matched few hotels in the world better than New York City’s Waldorf Astoria, but this bastion of gilded splendor is now closing for two to three years for a transformative makeover. The last guests were checking out by noon Wednesday after enjoying the rich Art Deco style of the old Waldorf one last time. When the building reopens, it will still have a hotel, but hundreds of its 1,400 guest rooms will have been converted into privately owned condominiums, according to a spokesman for the Anbang Insurance Group, the Chinese company that bought the storied hotel for nearly $2 billion in 2015.