Rossann Williams, Starbucks’ North American president, is leaving Starbucks and will be succeeded by the head the Asia Pacific division of the coffee chain.

Friday’s announcement marks the latest major change in the company’s interim CEO Howard Schultz. He returned to the top position in April following the departure of Kevin Johnson. After the board selects a long-term successor, Schultz will continue to serve the role until the end of the year. Schultz has stopped the stock buyback program of the company, pledged $1 billion to increase wages and improve cafeterias, and vocally opposed union efforts.

John Culver was the chief operating officer of the company. He wrote in a memo addressed to employees that “as we embark upon the next chapter, we have made an difficult, but necessary change at our North America business; change that creates new leaders for a new age at Starbucks,” CNBC viewed. “The decision was not made lightly. It was preceded by discussions about Rossann’s next opportunity within the company. She declined.”

Williams joined Starbucks in 2004 after working at Blockbuster and Toys ‘R us. She has been a prominent face of Starbucks’ efforts to stop unionization by its baristas over the past year. As of Friday, more than 150 Starbucks cafés across the U.S. voted to unionize.

Williams’s departure was first reported by The Wall Street Journal.

Williams will be succeeded by Sara Trilling, currently the president of Starbucks’ Asia Pacific company. Trilling takes over on Tuesday. Trilling joined the company in 1992, working as a creative director on its retail store design. She then moved up to become a senior manager. Williams will assist her in her transition through June. Cliff Burrows (president of the Americas division) will also be there to help.