SAN FRANCISCO :Three senior executives in Intel's manufacturing operations are set to retire, Intel told Reuters on Thursday, as new CEO Lip-Bu Tan implements sweeping change to resuscitate the struggling U.S. chipmaker. Intel told staff on Tuesday that corporate vice presidents in the technology development group, Kaizad Mistry and Ryan Russell, would retire, as would Gary Patton, corporate vice president at its Design Technology Platform organization and a former IBM executive. Intel also