Marni Walden, Verizon’s EVP and president of global media, plans to leave the company in February 2018, the telco announced Wednesday.

Walden, the highest-ranking female exec at Verizon, was the key driver of the company’s acquisition of Yahoo and the formation of Oath, which merged AOL and Yahoo. During her career spanning more than 20 years at the telco, she also served in senior roles for Verizon Wireless, including chief operating officer.

As of Dec. 31, 2017, Walden will step down from her current role, becoming a “strategic adviser” and continuing to report to Verizon CEO Lowell McAdam until her departure.

Following that date, Tim Armstrong, CEO of Oath, who will continue to be responsible for leading Oath, will report directly to McAdam. Walden has also overseen the telco’s Telematics organization, which after her exit will report to John Stratton, Verizon executive VP and president of global operations. In addition, Walden has led the company’s Strategy Development and Planning group.

“Marni helped build our wireless business, starting as a sales representative in a store, and grew into an inspirational leader and role model for so many at Verizon,” McAdam said in a statement. “She has most recently spearheaded Verizon’s entry into global digital media and telematics and will leave us in a strong competitive position.”

Before being named to her current position in February 2015, Walden was EVP and president of product and new business innovation. Before that, she was EVP and COO for Verizon Wireless after serving as chief marketing officer and president of the carrier’s 15-state Midwest area. Early in her career, she was branch director in Colorado and Wyoming for AirTouch Cellular, which became part of Verizon Wireless through a series of mergers.