Travis Kalanick wasn't the only CEO of Uber. Ryan Graves joined Uber in 2010 as the ride-hailing giant's first employee and served as the CEO, a position that Uber is now currently trying to fill, again.

On Thursday, Graves announced he's leaving his full-time position at the company. He will continue serving as the director of the company's board. Graves had been working as Uber's SVP of global operations.

Graves will spend the next month transitioning out of the role and leave my mid-September, according to an internal memo sent to employees.

"In some ways my focus going forward will not actually change very much — it remains all about people, and it’s clear to me the stability of our board of directors, the selection of our new CEO, and the empowerment of our management team is what is needed most," Graves wrote.

Uber declined to comment.

Uber has been in the midst of a major exodus of its executives after allegations of a company culture rife with sexism spurred an investigation and the exit of Kalanick. The graphic below shows how many of the company's top people have left:

Image: bob al-Greene/Mashable

As a board member, Graves will still be helping with the CEO search to replace Kalanick, who stepped down from the role in June.

The CEO search has been quite the mess, with reports of Kalanick telling people he wants to "Steve Jobs" (referencing the Apple cofounder returning to his company as CEO after being ousted), Recode reported. But Garrett Camp, Uber cofounder and board member, said Kalanick will not be returning, according to Recode.

Uber has been speaking with several potential replacements for Kalanick. Uber had approached Facebook’s Sheryl Sandberg, YouTube’s Susan Wojcicki, General Motors’ Mary Barra, EasyJet’s Carolyn McCall, and HP's Meg Whitman, all of whom have declined, according to The Washington Post. Three men, including GE's Jeffrey Immelt, reportedly remain on the shortlist.

Kalanick's removal, along with that of other top executives, came after reports of a toxic workplace culture, ignited by a blog post from former employee Susan Fowler Rigetti. Reports also exposed Uber's "Greyball" program, a tool for collecting data to circumvent government officials, which they could face criminal charges from. Uber is also in an ongoing legal battle with Waymo, Google's self-driving car division.

A March report from Business Insider revealed that Graves had been absent from Uber's offices. Part of Uber's scandal involved a poorly-managed HR department. Graves used to oversee HR.

"I wouldn't be surprised," an Uber employee told Business Insider about the possibility of Graves taking the fall.

Graves denied the allegations at the time in a series of tweets.

Here's the full letter from Graves:

Uber team —

In the past 7.5 years of building Uber, I’ve learned so many different lessons, one of which is the fact that people who embrace uncertainty and change have the best grip on reality. In the middle of September, I’ll be embracing another big change on my journey with Uber and will transition out of a full-time operating role to focus on my role as a Board Director.

In every position I’ve held at Uber, as GM, then CEO, then SVP of Global Operations, I’ve focused on people and team. Uber’s launch, our rapid growth, and now global impact, are all a testament to the quality of the folks that I have had the pleasure of working and growing with. That team is now the driving force behind the durability and importance of the business we run in over 600+ cities.

In some ways my focus going forward will not actually change very much — it remains all about people, and it’s clear to me the stability of our board of directors, the selection of our new CEO, and the empowerment of our management team is what is needed most. So I will do everything in my power to deliver on those goals for the benefit of our organization and the millions of people — riders, drivers, eaters and couriers — and their communities that Uber serves every day.

I could not possibly stress enough how insanely proud I am of this organization. The dedication towards our mission of providing transportation that can be trusted, to everyone, is noble. We, as a team, have achieved something that has truly changed the world for the better, and will continue to do so long into the future.

I also have deep gratitude for the lessons learned from Travis, from my colleagues on Uber’s ELT, and my Global Ops leadership team over the years — notably Rachel, Austin, Jo, Mac, Pierre, Droege, Penn, Jambu, Ro, Mike, Amit, Meghan, Barnes, and so many others who have given so much of their hearts and lives to building this company. Thank you. Without you, I wouldn’t be the person I am today and for that, I will forever be in your debt.

When you go through an experience like we have building Uber you forget that it’s not just the people across the desk that are making a huge investment, it’s also the partners and spouses, the families and the friends at home also making sacrifices. I would never have been able to make this journey without my wife Molly there to listen and advise. The ride hasn’t always been easy but nevertheless, she’s been there with me to laugh, to cry, to plan, and to celebrate. She deserves more credit than anyone in supporting me through it all. She’s been the most constant and enduring partner, right at my side, and building her own company and our family along the way. I *really* look forward to being able to return the love and spend more time with her and with our boys.

So, why now? Well, there is no great time for a move like this one. But it’s really important to me that this transition doesn’t take away from the importance of the onboarding process of our new CEO, whoever they might be. My hope is that ensuring my transition is known and planned for well before our board's decision on CEO it will help to make it clear to our team and to our new leader that I will be there to support however I can.

There is another lesson I’ve learned that we should have applied much earlier. We should have taken more time to reflect on our mistakes and make changes together. There always seemed to be another goal, another target, another business or city to launch. Confucius said that reflection is the noblest method to learn wisdom, and fortunately, our new found reflection and introspection has become an asset to us and we have evolved and grown considerably. Our culture, our processes, our leaders, and our teams have become wiser, stronger, and more mature because of it. Regardless of which role I hold in the future, I’ll be dedicated to supporting Uber’s leadership, partnering with Uber’s new CEO to understand the complexities of this business and this organization, and to continuing to deliver on the critically important mission and future we have ahead of us. Again, thank you all, and let's Uber on!