Sales of previously owned homes slumped in November to the lowest level since April 2014 as a change in industry rules lengthened the amount of time it took buyers to close on a deal. Closings on existing homes, which usually take place a month or two after a contract is signed, declined 10.5 percent to a 4.76 million annual rate after a revised 5.32 million pace in October, the National Association of Realtors said last week.