George Davies, Marks & Spencer's part-time chairman of Per Una, will retire next month amid a senior management restructure at the company.
Andrew Skinner has been appointed trading director for Per Una, in addition to his role as director of GM planning, and will report to executive director of clothing Kate Bostock. Helen Low, womenswear head of design for casualwear, will become product and design director for Per Una.
Annette Browne has been promoted to trading director for women's casualwear, Limited Collection and knitwear, and Bernadette Lusher will become trading director for women's formalwear, footwear and accessories.
Julian Kilmartin, trading director for menswear, will leave the business and will be replaced by Richard Price, head of merchandising for womenswear.
Melanie Davies, Per Una business unit director, will also leave Marks & Spencer.
M&S chairman Sir Stuart Rose said: "George has done a fantastic job in establishing Per Una and building it into a significant brand. We are immensely grateful to him for all he has done for M&S and wish him well for the future."