Research in Motion, maker of BlackBerry smartphones and tablets, fired its co-chief executives, effective immediately, and replaced them with Thorsten Heins, who had been RIM’s chief operating officer. He plans to take action quickly. The BlackBerry maker’s CEO said he will present the board with his plan for the company’s future in just a few of weeks.

The German-born executive took over from Lazaridis and Balsillie, two longstanding co-CEOs who turned the BlackBerry maker into a global company and a household name. They will remain on the board, and some analysts have expressed concerns that they would keep a prominent role in the future strategy of the company. Mr. Heins, however, made it clear that he would be the one making the decisions.

In order not to lose ground, RIM may have two main ways forward: (1) giving a stimulus to sales with the tablet PlayBook and the release of BlackBerry 10 OS or (2) a gradual shrinking of the company’s market share, with the company targeting a small number of corporate and governmental customers who want proprietary messaging and security features.