She took the job in the summer of 2016, three weeks before the Wells Fargo phony accounts scandal—in which bank employees created millions of unauthorized bank and credit card accounts—became big news. Mack didn’t know about the issues when she took the job, though she’s spent much of the time since dealing with fallout from the scandal and working to win back the trust of the bank’s customers, employees, and other stakeholders.

That effort has been considerable and multi-faceted Mack told an audience at Fortune’s Most Powerful Women Summit in Laguna Niguel, Calif., on Tuesday. “People ask me, ‘What’s the most important thing you did?’ It’s a lot of things that began to build a story that said ‘We’ve got your back, just trust us.’”

One important and swiftly executed early step was changing the compensation plan for Mack’s 72,000 employees—in three days. She had a “really smart” team that accomplished that over a weekend in September 2016, and the bank rolled out the new plan to its 6,200 locations on Monday.

“We needed to send a really strong message to our stakeholders, investors, team members, to our regulators, to the elected officials, around the fact that we did have a flawed incentive plan around sales goals and that was done,” said Mack.

She also stressed the importance of the company’s apology tour—that is what stakeholders wanted to hear, she said—and her listening tour, which has involved visiting hundreds of branches and talking with thousands of team members. In the beginning, these interactions were about figuring out what was happening; later on, it became about building trust.

She added that she was very conscious about being as transparent as possible and not making any “big reveals” to employees that served 2.2 million Wells Fargo customers every day. She wanted them to feel engaged and to have a voice. She brought in a team to reinvent the process in which the bank was engaging with its customers.

“My worry has been not just fixing things,” she said, “but fixing things forward.”