The Nashua Symphony Orchestra is broadening its reach — and changing its name in the process. Monday at a press conference hosted by Nashua’s mayor, Donnalee Lozeau, at City Hall, the orchestra will announce it’s renaming itself Symphony NH. Music director Jonathan McPhee, who also heads the Lexington Symphony and is Boston Ballet’s music director, says the symphony’s long-term goal “is to serve communities within the entire state.” The orchestra gives two concerts in Manchester next season, and McPhee says it hopes to expand into Concord, Portsmouth, and the rest of New Hampshire.