The Rockets’ offseason plans begin with their pursuit of a top free agent, starting with Lakers center Dwight Howard, but they don’t end there. The moves they hope will come next will be a major part of their sales pitch, a person with knowledge of that part of their presentation said. The Rockets intend to describe details about their plans after signing a free agent, according to the individual familiar with their strategy, including a shift to the pursuit of veterans rather than the sort of young prospects they have collected in recent seasons and a willingness to spend well into luxury tax territory. Howard and Clippers guard Chris Paul are considered the top players to become free agents July 1. Teams cannot talk to them or their representatives until then. In addition to the expected discussions about their current roster and coaching staff, the Rockets intend to emphasize that after this season, they will have all of their first-round picks and full mid-level exceptions along with several young assets who could be dealt to upgrade the roster with more veterans. Exceptions in offing If the Rockets sign a top free agent, their payroll soon would move between the salary cap and the luxury tax, giving them mid-level exceptions, worth roughly $23 million over four years, beginning next summer. By going over the salary cap this season, they will be able to offer an exception worth $5.4 million over two years, enough that on a team with one of the top free agents they could attract the sort of solid backup wing they would need after trimming the roster to have sufficient cap room for their free-agent pursuit. The Rockets have told agents for Francisco Garcia, Carlos Delfino and Aaron Brooks that they will not pick up contract options this month. That exception and veteran’s minimums could be used to shift to a much more experienced roster if the Rockets land a top free agent, a plan they apparently will make a significant part of their presentation.