There's been a shake-up at the highest levels of Hillary Clinton's presidential campaign. Campaign manager Patti Solis Doyle has been replaced with Maggie Williams. Williams, a longtime Clinton staffer and loyalist who served as Clinton's chief of staff when she was first lady, came on board the day of the New Hampshire primary, and has been an advisor to the campaign since.

The move was announced officially in an e-mail Solis Doyle sent to staff and a statement Clinton provided to the press. Both are below.

Solis Doyle's e-mail:

"Over a year ago Hillary launched her campaign for President.

"Her announcement began a historic effort that has inspired millions and brought hundreds of thousands to their feet all across this nation.

"I have been proud to manage this campaign, and prouder still to call Hillary my friend for more than sixteen years. I know that she will make a great President.

"This has already been the longest Presidential campaign in the history of our nation, and one that has required enormous sacrifices from all of us and our families.

"During the last month I have been working closely with my longtime friend, Maggie Williams.

"This week Maggie will begin to assume the duties of campaign manager. I will serve as a senior adviser to Hillary and the campaign and travel with Hillary from time to time on the road. Maggie is a remarkable person and I am confident that she will do a fabulous job.

"Although I will continue to see you all at headquarters, I would be remiss if I didn't thank each of you for your dedication, excellence, and passion over the last year.

"You are the best campaign staff in the history of Presidential politics and I am grateful to each of you for your hard work and friendship."

Clinton's statement: "Patti Solis Doyle has done an extraordinary job in getting us to this point -- within reach of the nomination -- and I am enormously grateful for her friendship and her outstanding work. And, as Patti has said, this already has been the longest presidential campaign in history and one that has required enormous sacrifices of everyone and our families. I look forward to her continued advice in the months ahead. Patti and I have worked with Maggie Williams for more than a decade. I am lucky to have Maggie on board and I know she will lead our campaign with great skill towards the nomination."