 WESTLAKE VILLAGE, Calif.--BUSINESS WIRE--PennyMac Mortgage Investment Trust NYSE: PMT today announced changes in the roles of certain of its executive officers in conjunction with organizational changes announced today by PennyMac Financial Services, Inc. NYSE: PFSI, PMTs manager and service provider. Andrew S. Chang, currently Senior Managing Director and Chief Financial Officer, will assume the new role of Senior Managing Director and Chief Operating Officer. Daniel S. Perotti, current 