Two downtown St. Petersburg restaurants are closing their doors for a bit and undergoing significant renovations.IL RITORNOHurricane Irma nudged Il Ritorno to close a week earlier than intended for construction. They anticipate being closed until late October.Chef and owner David Benstock and his wife, Erica, obtained the space behind their current location at 449 Central Ave. earlier this year and plan to expand into that space during the closure. In doing so, the modern Italian restaurant will double its 1,800-square-foot size.Among the features to be added in the larger space are a private dining room that will seat up to 14 people and an open kitchen with a bar at which diners can sit and watch chefs prepare their meal.Il Ritorno will acquire a liquor license in the process; previously they have served beer and wine only. Also, look for a menu change when the new space opens in the fall. (727) 897-5900. ilritornodowntown.com.CASSIS AMERICAN BRASSERIEAlong Beach Drive, Cassis American Brasserie closed Sunday and plans to reopen Friday in time for dinner with updated features including a remodeled indoor bar, a kitchen overhaul, a new sign and more.More changes will come in October to the spot at 170 Beach Drive NE, as the patio area along Second Avenue N will ditch the covered tables and chairs for a free-standing lounge area with cabanas and high-top tables. The space will also feature a new cocktail menu.The restaurant overseen by executive chef Jeremy Duclut, a champion of Chopped on the Food Network, opened in 2010. His culinary approach at Cassis is classic French brasserie staples with a handful of American comfort foods thrown into the mix. (727) 827-2927. cassisab.com.