Company says decision was voluntary Siebel Systems Inc.’s senior vice president of global services, Karen Riley, handed in her resignation Thursday, a spokesman said Friday.Riley’s resignation takes effect Jan. 1, 2004, when Siebel executive Herb Hunt will take over her duties. Siebel had no comment on why Riley is leaving the San Mateo, California, company, but a spokesman said the decision to depart was hers.Riley joined Siebel in 1999 after spending two decades at IBM Corp. in various software development and management roles, culminating in a position as general manager of IBM Global Services’ CRM (customer relationship management) and business processes unit. Hunt, her successor, also served as a top CRM executive at IBM before coming to Siebel, where he is currently chief technology officer and a group vice president. DatabasesSoftware DevelopmentTechnology Industry