Exxon Mobil Corp. (NYSE: XOM) is undergoing change at the executive leadership level with news June 8 of the retirement of its vice president of human resources and the intended retirement of its senior vice president.

Michael J. Dolan, senior vice president of Exxon Mobil, plans to retire effective Aug. 1 after 38 years of service, according to a news release. He has served in his current position since 2008.

During his career, Dolan has held several technical and managerial positions in the company’s global petroleum refining and petrochemical businesses. These included serving as regional director in ExxonMobil Chemical Co. for the Middle East and Africa, executive vice president of ExxonMobil Saudi Arabia, president of ExxonMobil Refining & Supply Co. and president of ExxonMobil Chemical Company in 2004 among other roles.

In other news, Exxon Mobil said Malcolm Farrant, vice president of human resources, has decided to retire after 35 years of service. Tracey Gunnlaugsson, president and CEO of ExxonMobil marine affiliate SeaRiver Maritime Inc., will step into the vice president of human resources position effective Aug. 1.

Farrant held several management positions with increasing responsibilities in marketing, lubricants and refining in the U.K., Europe and Singapore, according to a separate news release. In 2006, he was transferred to the U.S. and appointed vice president of basestocks, specialties and asphalt for ExxonMobil Lubricants & Specialties Co.

During his time with the company, Farrant has also served as downstream business analysis and financial reporting manager as well as executive assistant to the chairman.

Gunnlaugsson will move into the vice president of human resources position, having held various positions within SeaRiver and ExxonMobil Refining and Supply Co. Her titles have included manager of U.S. products supply operations and commercial operations manager, the release said.

In addition to having held advisory positions in investor relations, safety and environment, and strategic planning, Gunnlaugsson served as pipelines and distribution manager for Imperial Oil in Calgary, Canada, in 2012 before returning in 2014 to ExxonMobil Refining and Supply as manager of product optimization for the Americas, the release said. Gunnlaugsson was appointed in 2016 to her current position as president and CEO of SeaRiver Maritime Inc.