 WESTLAKE VILLAGE, Calif.--BUSINESS WIRE--PennyMac Financial Services, Inc. NYSE: PFSI today announced that Andrew S. Chang, currently Senior Managing Director and Chief Financial Officer, will become Senior Managing Director and Chief Operating Officer of the Company. In this new role, Mr. Chang will continue to oversee the Companys finance division and will add responsibilities for enterprise operations, including marketing, human resources, corporate administration and regulatory relatio 