"as she resigned" is correct and usable in written English.
You can use it when indicating that something happened at the same time as someone resigned. For example, "The company accepted her resignation as she resigned from her position."
Shares in her company, Martha Stewart Living Omnimedia, plunged as she resigned as chairman and CEO.See article: An indictment for Martha StewartMs Stewart is accused of dumping shares when forewarned of bad news about a cancer drug, Erbitux.
As she resigned she said: "It's clear that my role was just an act of political correctness and they [the Union] had no intention to actually engage with the BME rep position".
She resigned as soon as she sold the manuscript, and it won several prizes, including the Guardian children's fiction award.
More successful as a teacher than as a director, she resigned from the post in 1987.
Rebekah Brooks walked away with £10.8m from Rupert Murdoch's News Corporation as compensation after she resigned from her position as chief executive of News International at the height of the phone-hacking scandal, UK accounts published by News Corp show.
So furious with Gordon Brown, who described her behaviour as "unacceptable", that she resigned from the cabinet on the eve of the elections.
As a result, she resigned from the high-salary position.
As a result, she resigned from the Times-Herald.
Ms. Rice worked as an assistant district attorney in Brooklyn, and she resigned as a federal prosecutor in Philadelphia in the spring to return to Long Island for the race.
She resigned as Cameron's adviser and then as head of A4e in February, amid fraud investigations into the firm, but she remains its biggest shareholder.
When she was indicted last June she was stripped of her titles as chief executive and chairman of the board; in March she resigned as chief creative officer and a director of the company.
