Patryn, a former chief financial controller, was tapped interim CFO in May.
Nancy Bush, vice president and corporate controller, will take over as interim CFO.
Zwick had been CFO since 2012. Controller Eric Carlson has been tapped interim principal financial officer and interim principal accounting officer. The company is searching for a permanent CFO.
Hyatt is CFO, senior vice president and chief information officer at IHS, which acquired Polk in June.
Kaeser has been with the company for 33 years. Former CEO Peter Loescher was dismissed because of Siemens' flagging performance.
Chairman Eike Batista will take over CFO duties. No reason was given for Lazcano's departure.