Marks & Spencer has announced its chief executive, Sir Stuart Rose, will stay with the company for an extra two years, in a major management revamp.
Stuart Rose will become executive chairman from 1 June
Sir Stuart will stay with the firm until 2011. His original commitment was to stay until 2009.
The company also announced that Sir Stuart will be made executive chairman from 1 June, when the current chairman, Lord Burns, departs.
The company is also expanding the role of finance director, Ian Dyson.
In addition he will become director of operations with responsibility for the company's stores.
The extension of Sir Stuart's leadership at M&S gives the company stability during a tough time for retailers.
"There was no obvious successor," said Nick Bubb, an analyst at Pali International.
"This allows Stuart to work through the current downturn - I don't suppose he'd want to leave on a low note."
It is unusual for a firm of Marks & Spencer's size to combine the roles of chairman and executive.
But Sir Stuart has been credited with turning around the company's fortunes when he joined in 2004.
Sir Stuart Rose said: "Terry has been an excellent chairman and we are very grateful to him.
"In taking on the role of executive chairman, my task will be to guide the business through the next stage of growth."
In January M&S reported its worst quarter in more than two years.
UK like-for-like sales fell 2.2% in the last three months of 2007.
Sales of clothes and homeware declined 3.2%, while food sales dropped 1.5%.
Like other retailers M&S has been struggling to maintain profit growth as prices for clothes and home products has been falling.
In January Sir Stuart said that the UK High Street had "definitely slowed up" and conditions in the clothing market were tougher than they had been for 10 years.
In other top level changes, Kate Bostock and Steven Esom were promoted to the board.
Ms Bostock takes responsibility for clothing, except for the "per una" range, and Mr Esom remains in charge of food.