Did you know that the team who made Instagram had previously developed a product called Burbn? It was a check-in service similar to Foursquare except that it focused on hanging out with your friends. Needless to say, it never took off. The team performed something that is most visibly seen in the tech community: a company pivot. They changed their business focus and created Instagram. Not long after Facebook purchased the tiny company of 12 or so for $1 billion.
Sometimes companies need to change direction to survive. For more on corporate culture and the role of the mission statement, check out this article on shaping an authentic corporate culture.
A strategic change is a change in how the company tackles a problem. Going from print advertising for your business to online, for example, is a strategic change. As is targeting a different demographic or selling a new type of product. When Amazon launched the Kindle, that was a strategic change. When Microsoft revealed that Windows 8 had changed how the company had approached operating systems, that was a strategic change. Change management in this case means convincing your team of the new strategy's value.
An operational change is a change in the structure of your company. That could be a reorganization, lay offs, or just a team change due to a strategic or mission statement change.
Operational changes are some of the roughest for your employees because they never quite know what to expect. At least with a change in technology they aren't likely to find themselves without a job.
Technology is advancing inexorably, whether we like it or not. That means we need to keep upgrading or fall behind. Often operational and strategic changes are driven by a change in technology. At the turn of the century, for example, it was rare to see a TV commercial direct you to a website. Now it is commonplace.
A change in technology could mean a change that affects all your employees. If an operating system upgrade breaks a proprietary piece of software, you are going to have to retrain your team with the new software. Technological changes don't have to be rough, though. Switching to Intuit Quickbase is often quick and painless.
That said, people are stubborn. Often technological changes cause the most trouble. Make sure your team is trained for the software, though, and you should be able to avoid most of it.