Although the notions around career change have been in flux for a number of years, there is one identifiable thread running through the rhetoric of the past 50 years: always build on your old career and its well-developed competencies.
You won’t need all of your old competencies, but a significant number must be available to support your new career. Journalists love to report on the unique people who won’t follow that rule. But the number of people who build a successful career that ignores their previous competencies is miniscule. Analyzing the past can force you to define what’s transferable and what’s not. In the long run, the distinctions between the past and the future provide focus for gaining new learnings quickly and efficiently.

This approach has two significant advantages: it is not overwhelming—and it makes you immediately valuable to your (new) organization. I always assumed this was self-evident, but experience reveals that few really understand the process initially!
One of my mentees provides a superb example for successful change. About a dozen years ago, he got into a major financial firm right out of college as a client relationship specialist. An English major, his conversational and linguistic skills were superb. Though he did not initially recognize his giftedness, he almost automatically thought first in big pictures, then created or broke out process from that macro understanding. This unusual competency sometimes goes with a humanities degree, but is usually missing in those with technical and business degrees.
His use of that expertise was spontaneous and unconscious. Early on in the financial firm, he began using technology with his relational skills, the focus of the finance position. After just a couple years, he bumped up that elementary experience into making sense out of tech strategy, assessing internal tech needs--and working with technology folk. Pretty soon, though he’d never had any technical background in software, he began to understand technology process and strategy more richly. (You don’t need to know how to code to understand process and strategy). Soon, with articulate questioning and networking, he became adept at figuring out what various programs could and could not do. As a result of his curiosity and focus, he became an expert strategic and planning thinker. That led to project management in a leading tech firm. (Still no coding expertise.) But from that experience he recognized the value of Agile, got his credentials very quickly and was soon using Agile in his project management. Next, you guessed it, he got on the Scrum bandwagon and is now a Senior Scrum consultant. I suspect there’ll be still further vocational and growth moves.
His career development model is simple and straight-forward: develop by adding strategic tools.
Sure, this sounds like overly simple process. Yet, the model is fundamental to all career change. Surprisingly, no more than five to ten percent of business folk seem to have the understanding and discipline to follow the model. Indeed, my observation of several hundred individuals attempting to develop skills without anchoring growth in the past reveals ongoing, unnecessary limitations.
Why is that?
Edgar Schein of MIT has talked and written about this macro problem for years. More recently, Herminia Ibarra has also been dealing with this same issue. They believe that when the gap between your present situation and the hoped-for new situation is too large, the more likely it'll be that you'll ignore or misunderstand the information in the new context. And the result will be—failure...