John Chen, Chairman and CEO of Sybase Inc., speaks at the Reuters Global Technology Summit in New York in this file photo taken May 18, 2009. BlackBerry Ltd has no plans to shut down its loss-making handset business, incoming interim Chief Executive John Chen said on Nov 4, 2013, adding that the smartphone maker has sufficient resources to stage a turnaround. [Photo/Agencies]

BlackBerry named John Chen, credited with turning around Sybase Inc in the late 1990s, as its interim CEO and executive chairman. Sybase, an enterprise software company, was eventually acquired by SAP AG in 2010.

Chen's appointment was a surprise to investors as was the departure of current CEO Thorsten Heins, who will leave in about two weeks after the debt offering is completed. The company gave no reasons for the change.

BlackBerry, based in Waterloo, Ontario, pioneered on-the-go email, and for years its pagers and phones were must-have devices for political and business leaders. But it has bled market share to Apple Inc's iPhone and devices that powered by Google Inc's Android software.

In an interview with Reuters, Chen stressed his experience as a turnaround artist, and said he has no interest in shutting BlackBerry's loss-making handset business.

"I'm doing this for the long term. I'm going to rebuild this company," said Chen, who said it would take six quarters to turn BlackBerry around. "I know we have enough ingredients to build a long-term sustainable business. I've done this before and seen the same movie before."

Chen, who joined private equity group Silver Lake as senior adviser a year ago, said his involvement with BlackBerry has nothing to do with his ties to Silver Lake, which partnered with Michael Dell recently to take computer-maker Dell Inc private.

"Fairfax's investment will buy the company some time, which it badly needs, but the company needs a new strategy more than ever," said Jan Dawson, Ovum's chief telecoms analyst, noting that communication on the strategy must start "very soon".

BlackBerry said Watsa, who stepped down pending BlackBerry's strategic review, is rejoining its board as lead director and chair of its compensation, nomination and governance committee. Chen replaces Barbara Stymiest, as chair of BlackBerry's board, while Heins and David Kerr are also stepping down.

Heins has been BlackBerry CEO for less than two years. In April 2013, the board agreed to a new pay deal that included generous payments if Heins lost his job due to a change in control, or if he was terminated without cause, including two years' salary and a variety of other incentive payments.