Cheshire said: "It has been a great privilege to get to know my Debenhams colleagues over the past three years". The stalwart of British shopping districts, which has struggled to keep pace with Amazon.com Inc. and other online retailers, said discounting will likely hurt its gross margin in the first half, following three profit warnings a year ago.
Following the Debenhams annual meeting on Thursday, Mr Cheshire stepped down as chairman immediately, but Mr Bucher will stay on as chief executive, although not as a director. He was appointed chairman in April 2016.
For the 18 weeks, group gross transaction value declined 5.6 percent, with like-for-like sales down 5.7 percent.
Debenhams is now on a desperate quest to drive down costs, and central to this is a plan to extend previously announced store closures from 10 to a possible 50 sites over the next three to five years.
Two major shareholders have ousted the retailer's chairman, Sir Ian Cheshire, from the board.
However it added: "Of the votes cast".
The board said it is "mindful of its responsibilities to all shareholders" and has full confidence in Bucher and in the management's plan to reshape the business.
Every director up for re-election received over 11% of votes against their re-election.
As a result, Cheshire will step down from his role, deciding it "is no longer possible for him to remain chair".
In September, Sports Direct ruled out a takeover bid, shortly after an outgoing director said the board had discussed combining Debenhams with the House of Fraser chain that Sports Direct bought out of administration in August for 90 million pounds. "Excluding those two shareholders, the vote for Sergio to continue on the board was approximately 99.6% in favour".
The dramatic events came after weeks of pressure for change at Debenhams from Ashley as the debt-laden store chain struggles to turn around a slump in sales and profits.
Duddy said "I recognise that individual shareholders have wished to register their dissatisfaction".
Sports Direct's stake in Debenhams is just under 30%. I am looking forward to working with Sergio.
Mr Duddy added that his first task as interim chairman would be to meet shareholders "to understand any concerns that they may have".
Bucher said: "We responded to a significant increase in promotional activity in the market, particularly in key seasonal categories, in order to remain competitive for our customers".
Debenhams said it had started talks with its bankers about refinancing.