Twitter"s design and engineering heads will step down from their roles as part of a management restructuring campaign LONDON: Twitter Inc. said on Friday its engineering head Michael Montano and design chief Dantley Davis would step down from their roles by the end of this month, as part of a broader management restructuring at the social networking site. The moves come just days after co-founder Jack Dorsey stepped down as chief executive officer and handed over the reins to Chief Technology Officer Parag Agrawal. Twitter said Agrawal, in his newly assumed role, has decided to reorganize the leadership structure at the company and shift to a general manager model for consumer, revenue and core tech that would oversee all core teams across engineering, product management, design and research. Product lead Kayvon Beykpour, revenue product lead Bruce Falck and Vice President of Engineering Nick Caldwell will now lead the three units respectively, the company said. Twitter added Lindsey Iannucci, a senior operations and strategy executive at the company, would be the chief of staff.